Tough question. Worth checking out, yes, but that's almost just for batshit insane story moments and sick boss fights/concepts.
Gameplay, has it held up? That's tougher. I think the controls for 2&3 especially show their age. They're very fiddly.
FWIW, I came to the series very late. Probably 2013ish on the release of The Legacy Collection for PS3.
It's the red headed stepchild of the franchise but I really enjoy it. It would have been so easy for From to make Dark Souls 1.5 but they tried to do something different.
And the fact that there's some differences in NG+? chef's kiss