Tales and Chronicles
Jewel of the North, formerly know as vincegetorix
This.You have to do something to make it possible. If you are just swinging away and the invisible bad guy can see you, it's effectively impossible. IMO, obvs.
Invisible means Invisible, Blind means Blind.
If all conditions do is give yet-another instance of non-stacking Disadvantage, no wonder people focus on whittling the enemies HP to 0 instead of going for debuffs. Why would I was a 2nd level spellslot to blind a target when a cantrip impose the same penalty?