The stock cab block (and even the old one) has one big advantage to those who are proficient with it: being able to manipulate mic type, distance, offset, and angle within the same spot is VERY convenient to reach a sound in your head. It’s a lot faster than flipping through IRs.
I realize everyone is different, but to me the cab block or an IR is just a means to an end—a way to get a specific frequency balance & character that sounds reasonably realistic.
It matters less to me if it sounds exactly like some dude’s specific Greenback and vintage mic, because I wouldn’t know the difference anyway. But being able to quickly sculpt the right tonality/frequency balance is everything in a mix.
I say this as someone who has hundreds of dollars in IRs from York, OwnHammer, and others. The utility of them has really diminished over the years for me. It might be a different story if they had a slick way to manage them just like the new stock cabs do.