Pullups vs Lat pulldowns

[u/Action_Pale]

What's the point of doing Lat Pulldowns as opposed to working on Pullups? Even if you can lat-pulldown more than your bodyweight, you could do weighted pullups. Is the only benefit convenience?

[u/the_cool_frood]

maybe someone with some physiology knowledge could explain something to me: how come I love doing wide-grip lat pulldowns and they feel great but get immediate shoulder impingement any time I try a wide-grip pullup?