They qualify for the group stages fairly regularly, and even when they drop into the Europa League they often go on a decent run. They beat Lazio twice in that competition as recently as last season. We're talking about a player who's surplus to requirements at Brighton here.
The second part sounds right on paper, I'm just not sure it stands up to much scrutiny. Playing for Celtic didn't harm the international career of Mikael Lustig, to take a recent example of a not too dissimilar player performing for a comparable international side.