I don’t know how it feels within the industry, but as a viewer it feels like there’s an element of deliberate showiness with these de-ageing effects, especially recently (now that they can be done fairly well).
I have no trouble with suspending my disbelief as a viewer and accepting a different actor as a younger version of a character. But it’s undeniably impressive when you see something like RDJ in Civil War (the best example of digital de-ageing that I’ve seen so far), and you feel like you’re really seeing a performance from the same actor decades ago.
Those effects get people talking in a way that casting a younger actor doesn’t. Whether that makes it worth the time and expense needed to pull those effects off, I don’t know.