One obvious tradeoff is how delicate your funds will be on this thing among noobs... If all you have to do is push a little button at the end and shake this thing to make it throw away it's xpub/privkeys and generate new ones, then crap, this thing is going to lose so many noobies' funds it isn't funny.

Obviously it has to be powered on to do that so just walking around with it in your pocket isn't a concern, but once they plug it in and don't know what they're doing it's quite scary.