Funny. What you're claiming to be a solution is not the same thing and that's exactly how you make a bugged trophy which is a big hassle to anyone who care about trophy. If you do that, your save progress wouldn't match your trophy progress. For example, imagine a trophy that requires you to get a gold on every event, and say there are 190 events which takes 100 hours to finish.
Under your scheme, if a random user had 8 random offline golds and doesn't remember which for a variety of reasons (e.g. they didn't care to remember, or they just forgot, or they thought they've never played it offline but there are some golds which were never registered on the server due to short network malfunctions, etc at the moment of their acquisitions), then they would see 190/190 gold on their save file, but they wouldn't get the trophy as server only got 182/190 gold. There is no way to find out which ones are missing unless the developer also implemented an additional UI and functionality just for that (which almost no developers do and it also makes things more complicated for no good reason and increases the chance of potential bugs). As a result, only thing they could do is playing the entire 190 events from the start again in the hope of fixing the bug.