I use Bard simply because its one less login screen (ChatGPT has an aggressive cookie expiry afaict) and it has up to date info with sources typically available. If it could reliably provide source info thatd be great for API/library documentation while programming or random numerical and finance (what is X company’s price to sales?) searches I do all day.
Bard is the only reason why i don't pay for ChatGPT.
I use bard to write out my user stories and acceptance criteria and also as a grammar checker.