Some songs are just not meant to be fast...and I have heard FAR too many things speeded up for some purpose I just don't comprehend. Just to cram more into a space? For adrenaline? To prove you can play fast? .....I dunno.

Take the song "Shawnee Town", which is about poleing and rowing a boat....it truly suffers at Bluegrass tempo...
   ...and pumping shanties! They NEED a slow tempo to get the feel of what was going on.

There are cute 'patter' songs which are fun to zip thru, but mercy! It ain't a race!