Help, I have a query!

So I was just thinking about who else I could take in to the jungle, not necessarily because they're meta, but because they might be useful. And I realised that bard on paper seems like a decent jungler! I know he would have a low clear speed, but his abilities and utility would make up for that in his ganks which could be very strong! Is there a reason that bard isn't a good idea for a jungler? Or is he just not as efficient as other junglers, which in turn makes him a bad pick?

Thank you!