There's one and we've discussed it before.
The clutch (the device, rather than the pedal) is more than just a disc that makes changing gears by yourself possible. It's a control device - specifically a control device that governs how the power (okay, okay... torque) from the engine reaches the wheels.
The clutch pedal itself is an analogue input device to control the clutch. To be wholly fair, most drivers don't use it as one - they mash the pedal down, slam it into gear and hoof straight off it, without any consideration of continuity of power (okay, okay... torque) delivery and the comfort of their passengers, as you've noted - but it is one and used properly it's nothing but beneficial. I'd even go as far as saying it's a safety device - though that depends on circumstances.
It's a hindrance to outright pace in sports driving - a DCT and even an auto (let's disregard typical auto gear ratios) can get from gear to gear faster than someone rowing it themselves - and there's been so many TLGPs won and lost by a boneheaded clutch drag or gearchange, but it is a useful additional tool for driving over DCT, CVT or auto.
I'll add here that I've not driven many autos or DCTs compared to manuals. The list is quite small - Jaguar XJ6, Jaguar S-Type R and Mazda Xedos 9 (Millenia) Miller in the autos, Nissan GT-R for the DCT and Nissan 370Z for auto with flappy paddles. The only direct comparison I can make is the 370Z, because I've also driven a manual. I'll say I flubbed my very first gearchange in the manual 370Z - being on the left of the car didn't help - while that never happened in the flappy auto, but thereafter the clutch helped getting off the line in the adverse weather conditions compared to the flappy auto. Both cars had disabled (on purpose) traction control systems
Interesting that you would say the clutch helps in this scenario, because I've found that the clutch can be a hindrance when it comes to smooth power delivery, especially when you want to achieve extreme slow speeds. Starting in snow, for example, where you might want spin your wheels very slowly - the clutch certainly allows you to do that, but it requires that you burn your clutch the entire time you want to move your wheels slowly. You can't let the clutch out fully until you've reached a minimum speed - and that means riding a clutch that wasn't really designed to be ridden while you're moving at less than that speed.
Obviously you can get either a manual or automatic out of the mud or snow. Having the option to hold 1st gear can be good, but you have that in an automatic or DCT as well. In the end, you end up doing more damage to your manual than an auto. I don't know how the DCT handles that scenario - I've never driven a DCT in anything but ideal conditions.
For smooth gear shifting, I prefer an automatic over even a very talented manual driver. For applying the power slowly, I prefer an automatic - especially in reverse.
When I'm playing piano, I find it much more interesting to use the sustain pedal and play with both hands than simply using my right hand to play along to accompaniment. I'm still playing music either way and I can play the same songs with all parts and tones intact, but it's more fulfilling/interesting/engaging/enjoyable to get my whole body involved.
Do your use your left foot when playing the piano? Didn't think so. You're just as involved playing the piano as driving an automatic. You'd have done better to say drums which require both feet.
(If you're left handed and use your left foot, pretend I said "both feet")
I admit that certain songs may be easier to play with one hand + accompaniment, but that ultimately comes down to lack of practice. Playing with one hand may also enable me to eat a sandwich at the same time, but if I'm sitting at the piano, I'm there to play music, not to do other things. Other benefits of playing without accompaniment include being able to skip to another part of a song if I want to, and to improvise a new melody or song myself.
Actually I think the piano analogy fits my argument better than yours. I assume you play electric so that you can also control the various sounds that the piano creates, and you use the bending device so that you can slide from one note to another. Your piano of choice probably has as many controls as you can possibly cram into a room:
I doubt it. You probably play something a little more like this:
Why? Because that's what you're used to, it's what you've romanticized, it's traditional. Interestingly enough, I do the same thing. But it's because I don't improvise or create art with the piano, I recite art that has already been created.
With the guitar I play a little differently, and I have no problem having some aspects of guitar playing automated for me. Plenty of distortion effects that I could create myself but why bother when I have a pedal that can do that.
I'm not seeing how this doesn't just lend credence to the quote you were presumably trying to rebut.
I was pointing out the manual > DCT arguments that I have not rebutted and concluding that it was not significant for the massive benefits of DCT (speed, convenience, accuracy).