They’re not cheap, but they’re WAY cheaper to fly per hour than most other modern strike fighters by a pretty large margin. Also, one of their primary design criteria was to be a QRF/frontline/austere deployment aircraft - that is, one of the requirements was “you can pull this fucker out onto a straight stretch of highway, gas it up, slap missiles on, and start fragging hostile air right away”. That’s precisely the sort of system Ukraine would seriously benefit from.

Don’t get me wrong - the Vipers they’re using now are great, extremely flexible, and genuinely the bar-none best two-circle gunfighter ever built, but they are fragile as hell, and their support footprint is WAY larger.