Except that you have to fail several times in GG to lose.
BB you make two mistakes you're gone. Not unlike Marvel. Kappa
You actually got this backwards. GG is setplay city, one fuck up is half life into knockdown and setplay. In BB you can get snowballed too but it's not actually as crazy as it is in GG. GG is the grand daddy of ASW setplay.
Edit: A bit more in depth, that type of Slayer mix up is on the weaker end in GG btw, lots of ways to deal with that. The main thing in GG is that the game has a static knockdown state. "Anne, the characters have different wake up timings though." Yeah, but that doesn't change the fact that the same knockdown will force the same char to wake up on the same frame. Everybody in the cast can force a hard knockdown, everybody can force a mix up or safejump and most everybody can force a dumb one at that. The only thing stopping every game from ending in one hit is that conversions in GG get pretty specific and you can blow resources to try and get out of death. "Yeah, those defensive options make it so you can deal with GG offense." Kind of. They won't get you out of a mix up straight up unless you burst usually. Faultless Defense, Dead Angle, etc all stop people from continuing to extend on you.
Blazblue has a roll and variable wake up timings that the player controls. You can cover those options with pretty much everybody, but you give up a stronger mix up (usually) in order to do that. The characters that have setplay tools built into their kit can obv cover roll and mix you up, but it's not as universal a thing of knocking somebody down and running whatever bullshit you got on them. Blazblue has a lot of the same defensive options as GG (and Barrier is a free resource at that) so that's not too different. The difference in BB is that pressure is better on the ground and you can get easily mixed up out of pressure. Those defensive options help in that a lot, but it will still happen. Also BB combos tend to let you turn smaller hits into at least a conversion into knockdown. That type of knockdown tends to not be strong, but it can get at least pressure which is p good in BB.
End result is that in BB you can get oppressed from a small mistake, but you rarely get outright killed or vortexed immediately from a knockdown or something. In Xrd, damage is high enough that 2 hits can kill you and almost any knockdown can turn into some hilarious mix up. Both games are extremely momentum heavy, yeah, but GG is definitely more on the end of "fuck up once, end round on the next mix up" while BB is "fuck up once, end up in extended pressure that might end the round".