This is with the caveat that you are a lot more experienced of a bard player than I am. Obviously everyone will figure out you have the edge soon enough. However, I think it still lands kills. Most players can't track your health % when you're feigning weakness. They have some idea, but "convulsing" could mean so many things. Just this gap in information between players is bound to sway fights now and then.

I landed a lot of kills, including against good players (one 1v2 against Sindrir and Yaztren comes to mind), where I think overconfidence due to feign weakness played a significant role.