Question2: can I play games by the use of altcoin or just bitcoins?
There is no way you can earn bitcoins while enjoying your free time in gambling. In gambling, you need to spend money to get fun and if you're lucky then only can make some money but there is no guaranty that you will earn money.
There are many trusted sites accept few altcoins apart from bitcoins so it is up to you whether you want to play with bitcoins or altcoins. I mostly play with bitcoins and sometimes played with altcoins as well. I made some money from cricket betting and never made money from a dice game.