Doge has a few advantages over other coins a) it always works and never goes down, never had hard forks and never has problems that need to be reversed and b) it is on all the exchanges, it's on all the gambling sites and the fee is low. Last year when bitcoin fees were eye-watering, I was using Doge to move money from exchange to exchange. Steem's fee is low but it's only on a few exchanges, so you can't really use it. Doge is hanging on because it is the only thing that functions like an actual currency.