Boost weak yes...
It could be competitive if the AI has racing tyres and I have sport tyres, but that isn't really racing now is it? That's just a catch up mission on hard difficulty. And the miserable payouts are not worth the effort at all. If this had dynamic payouts (as well as superior) like GT Sport custom races had, now that would be worth the effort.
Doing a 10 lap race with a far weaker car and winning some decent credits to be able to buy quite a few parts on one of the many cars I plan to tune. That would be worth it.
Doing a 10 lap race with a far weaker car and winning ... not even enough to buy a set of racing soft tyres? ... Bruh
You probably don't mind because you don't want all the cars and also tune them. I not only want to have all of them, but also almost all of them in duplicates, one stock, one fully tuned, and in some cases, one for top speed. And even some racing car duplicates to create a custom race with several cars with different liveries would also be nice.
GT7 is also not the only game I play. So I really need good ways, and less boring (same 3 races to grind for 3 months starts to affect your sanity a bit), to get credits. Custom Races are not one of them, and Sport Mode while competitive, starts to get stale with the same old stupid rolling starts with massive gaps between cars, and their payouts are even more insulting than custom races.
Different ways to play the game... I've collected all cars in all Gran Turismos I've played, but GT7 is the one that makes me go the extra level because the cars' detail and customization are just on a higher level, and yet it's the one that makes life that much more difficult to do so. *sigh