I don't know about 'need', but I like to watch musical performances and a big part of the musical performance is... The singing. That's the music part! They don't play instruments! I like their songs and therefore when I watch them performing I want to hear them sing. I want to hear their voices because I like them. What do you watch musical performances for?
If I just wanted to watch a dance performance then there's studio choom and all the dance practices. If I just wanted a dance performance maybe I'm better off just watching professional dance crews doing their thing?
The choreo in kpop already takes into account that they'll be singing, so they should sing! I mean mostly they only sing one at a time, so I really can't see why they don't.
I like to watch their music performances where they don't dance as well.
Look, I am never out here hating groups that lip sync, they obviously have their fans and sometimes it's not up to the group to lip sync or not, but I pretty much only prefer groups that do sing live.
