I think I'm biased towards flash games, even bad ones, because they're at least games in the usual sense of the word rather than vehicles for ads and microtransactions.I have to disagree there, they're both equally bad. There were good flash games out there but to say that the average flash site wasn't completely overblown with dreadfully bad and low-effort games like mobile stores are now is looking at the past with rose colored glasses. Both are plagued by the same problem: anyone could look up "how do i make a flash game" in google and be quickly on their way to making their own little piece of hot garbage. 15 years later nothing has changed, and people can with the same amount of effort and talent (read: none) make a game that is equally bad, except now it's in badly rendered 3D instead of MSPaint 2D.
The only thing that's worse about modern phone games is that they're printing pennies for a pajeet somewhere because they filled it with ads, whereas people used to make shitty flash games only for the novelty of it.