Board Game Arena

I'm not sure if this is something that can be changed specific to cribbage or if it's just the way BGA works, but it looks like the change in ELO after a game is based only on the players' relative rank going in, not on the final score. I just played the same opponent twice in a row, with one win each, and so my ELO ended up right back where it started - but the game I won was a skunking, and the game I lost, I lost by one point. Seems to me it would be more realistic to improve the ranking more after a blow-out victory than a nail-biter!

Sadly ELO cannot reflect any detailed aspect of games but only player ranking (essentially win/loss in 2-player games).
This is not limited to BGA Cribbage. Whether a win be a narrow victory or a total domination, both count as a win nonetheless.

It’s impossible to know whether a skunking is caused by great play skill or just good luck. In Yahtzee for example a wide margin of victory is almost always down to luck whereas a 1 point victory can be an indication of great skill.

ELO doesn’t attempt to model that - it just asks “how good was your opponent, and did you win or lose?” For all games.