Blowtorch - hardware store vs kitchen store. Is there a difference?
Yes, there is no real difference.

Be aware that if you one from the hardware store, it should be one where the flame does not fluctuate when you tilt the torch. This usually happens with the very cheap ones. This becomes a big problem when you try to uniformly brown something. 

Aside from that and maybe "esthetically" I see no reason not to use one from the hardware store.