In most cases, it doesn't seem right to continue. I just resign. An early blunder could warrant some excessive play for the sake of actually playing the game.
However, if the pieces are exceptionally weird, yes, it can justify playing on in a technically lost position.
I am happy to oblige an opponent who wishes to play on if they've lost, except if the skill difference is too great.
I think in general the more different a variant is from standard chess, the more likely I am to play on in a lost position, with part of the reasoning being that I'm more likely to learn something new from playing on in a lost position, if I'm playing a variant, than if I'm playing standard chess. Would you say that you are also more likely to play on until mate if you are playing a chess variant than if you are playing standard chess?