Well the thing is 90% of the time you would do a meaty b23 on wakeup, you could instead just wait and whiff punish whatever you would stuff.
Why would I do it 90% of the time? I can also run up to you and do command grab, f.223, 22xxHM, Mb f.3... The opponent can't get out of that spot until you start so they have to make a 1/3 guess. Do a regular wake-up, do a MB rebuttal, or block. The only problem?
MB f.3 beats wake-up and MB rebuttal (because you can hold and dash cancel it)
b.23 will outspeed most MB b./f.3s, crush a lot of wake-ups, but loses to guarding.
Command grab will lose to a few of them, but if you have them respecting the fact that your first 2 cover those bases then you're set.
So what does the opponent do? Risk a wake-up when your main options beat them? Block knowing that they can only punish if you decide to do the b.23 option?
You have the 2/3 chance of winning out, and you cover all the options. As far as waiting, if you wait they have a chance to backdash. The point of this is it sinks into a sweet spot, a 5 frame gap on wake-up where if they don't input a wake-up option they are forced to reset into neutral, meaning they can't jump or backdash. I have a video of Bane doing it, and Shazam works off the same concept.
If the opponent tries to, they get opened up for free.
Its not an end-all, but its a hell of a start. And b.23, it crushes a lot more than just a few wake-ups. This thing I'm telling you alone would make the shazam/BA MU a 5-5, dead even.