The biggest disadvantages of Bitcoins are can't be use in the actual store because bitcoin is intangible and bitcoin can be lost instantly in your wallet if the file corrupted.
Hmm.. Bitcoin is accepted by several stores online. Actually there are lots of stores accepting it. And as a matter of fact there are some offline store like restaurant that accept bitcoin as payment. In my country i known 1 place where they accept bitcoin as payment. And it is where the meet up of Bitcoin Enthusiast people is always held.