I most of the time use BTC as it is accepted all over and has more users , so more demand and supply. But I know this guy who has moved away from BTC to Doge as it is too mostly acceptable and comes with low transactional fees. Few of the sites to use your Doge coins are - PLayamo, Crypto-games, Luckygames, 999Dice, DogeJack and many more. Such sites also allow to trade your Doge with other crypto.
It's more likely to exchange your doge to other crypto, but it requires you higher fee rather than on regular exchange site. You are only can exchange to crypto which accepted in those gambling site (you forgot to mention bitsler & fortunejack, you are also can betting with dogecoin on there)