Look, we can argue all day about whether Gigantamaxing sucks, whether it's a waste of space that came at the expense of other things like [REDACTED], whether they should've just done new Megas, so on and so forth.
But if there's one thing Gigantamaxing has already done better than Mega Evolutions did in their debut it's that a substantial amount are actually being given to Pokemon from their generation of origin this time. No matter how much you like Megas and decry GF for scrapping them, the fact only one Gen 6 mon (a Mythical no less, so basically useless for Game Freak-sanctioned competitive formats) got a Mega throughout that generation's entire run is still fucking stupid. And while you can say Gen 7 started this trend with exclusive Z-Moves being given largely to Gen 7 mons, those were far more undercooked and didn't change the Pokemon they were used by too much, not like Gigantamaxing giving them new forms entirely. In addition, those were only given to popular and "marketable" picks like the starters, mascot legends and Mimikyu, whereas the Galar Pokemon Gigantamax forms seem to have a way more varied distribution.