Despite most governments do not recognize Bitcoin as a currency, all those restrictions and existing laws relating to online and mobile gambling apply to bitcoin gambling. If online gambling with fiat money is illegal in your jurisdiction, then it is also illegal with BTC.
so far here in my country gambling is not illegal because we also have many casino's here both online and house casino's in regards to bitcoin casino it is not illegal yet as of now as far as i know because bitcoin is not yet been that popular and the goverment is not yet inform about how big bitcoin can be so they are not doing anything yet but i know if they found out how big is bitcoin restriction will follow to get money from the owner of btc gambling site.