IMO using altcoin (such as Doge) is more practical. There are times when Bitcoin mempool is full which makes transaction fee very expensive.
Possibly. But then how will the server get its balance in the altcoin? Unless you're suggesting we hold a hot wallet stocked with the altcoin of choice... which is risky if the altcoin dips. What's the transaction fee like for ETH? That's one of the most stable altcoins I know. Will check it out.
What i mean is player who join out of financial motivation is likely to be less friendly and use deceptive tactic to earn money.
No doubt about it. I'm sure we can find a way to moderate in-game transactions, however, to prevent or dissuade/discourage scams in-game. What kinds of deceptive tactics are you thinking of?