Regenerate basically saves a creature from destruction one time, whether thats in combat or otherwise
It is worth noting that the Mega Dream EX set includes unique illustrations exclusive to the Japanese edition, enhancing its value for collectors
I was fortunate enough to get one in a Booster Box, but you can find it for fairly cheap on TCGPlayer, with a card that is a must-have addition to your library
Removal like Lightning Axe and Path to Exile, draw spells like Chart A Course, and cards that provide extra turns such as Temporal Tresspass are some of the best targets you can find
But at the end of the day, it's always going to have value because this is a game about creatures attacking and blocking, and this will do so very nicely, either as a 4/4 flying haste-ed one, or just a 5/5 flying that can also shoot stuff if properly en-countered (say, by putting the counter on and not immediately swinging)
It felt a little odd to then blink something