I'm sure if I loaded the cutter in your photograph, even sans the back bevel and with those very tiny scratches, I would find it to be blistering sharp and more than up to snuff.
Possibly. Probably even. I do know that the same blade with a flat back becomes noticeably sharper when given that little back bevel. Even with oilstones. Granted, my oilstones still haven't worn in properly, since they're still able to put an edge on danged near anything I want them to. It's not a 'blisteringly sharp' edge, but the edge works.
Like I keep saying, if you're satisfied with what you've got, be happy and stick with it. I figure that little bit extra is so close and easy to access, why not have it?
What stands out to me is that even with so much information out there, so many different ways to get things sharp and folks still have trouble with it.
It's not difficult, we both know that.
At the same time, I often get asked for assistance and when I answer I have to make absolutely sure that what I say/write will get a result.
So, for a plane blade I recommend that small back bevel with a ruler. It negates any defects in a blade back for the most part. So someone having trouble getting things sharp has one less thing to be concerned with. And if they still run into trouble, there's something bigger and uglier in the way than not having a flat back.
Get stuff sharp first. Get it sharp consistently second. Then go play, work out what you want to get and how you want to get it.