if I wanted to exchange bitcoin (equivalent to $1000) for $1000 USDT, then with the swap I I can get not $1000, but, for example, $997.89.
Comparably to swap-exchanges like Boltz, I think that a ~0.2% a pretty good deal.
If I want to speculate in the short/medium term in volatile markets, then Bitcoin is not the best choice.
I don't know what makes you say that with such confidence. You know absolutely nothing about an altcoin, unless you have insider information, which is not the case for the vast majority of retail traders. You know nothing about bitcoin in the short-term either, but at least you know it can't disappear.