"... the distinctions ... " Yes! Those are crucial distinctions, indeed. As I understand it, polyamory is centered on the -amory part: love. And if I understand right, swingers are more interested in sexual adventuring which isn't centered on a "heart connection", as I like to call them.
As much as I enjoy sex, I don't imagine I will ever again have "casual" sex -- if ever I did. There has always been some "heart" (love) involved, if not always the intention of a long term, "serious", and commited relationship. I don't think love has to last forever, or be nurtured regularly over a lifetime, to be real love. But I do prefer the many powerful advantages of commitment to loving over time!