I don't hate Myes Turner as a player, the C's could do worse at center. He's also just 7 months older than Jaylen, so he fits the C's timeline.
He just feels a little overpriced, and perhaps more importantly his greatest weakness is defensive rebounding which the Celtics are already pretty bad at.
I'd take him if the asset price was low enough, but I sort of think there are options that make more sense financially. I don't know, he's just always struck me as a guy who's never quite as actually good as his skill set suggests he should be.