Can I ask a question? If I get Gatcoin ( or reward) from restaurant A. can I use it at restaurant B (use Gatcoin platform too)
Yes of course we like answering questions as it helps us know what the crypto community is thinking!
Restaurant A would issue its own branded token. You would need to take this token to the GAT Exchange and sell it there for GAT Coin. You could then use this GAT Coin to buy tokens for Restaurant B (or hold them, or trade them on an external exchange)
You can see this process mapped out in our overview
https://www.gatcoin.io/wp-content/uploads/2017/09/170928v2-GATCOIN-System-Overview.pdf