It depends on what you typically use a tablet for. If its media consumption, this is a viable option. If its simple spreadsheet and word document work, then its viable if portability is important. Anything more and its probably best to get a tablet.I think we are looking at this device very differently. And I don't think either is right or wrong.
I am with MKBHD where he questions who this phone is for, and whilst it may be the best foldable it's still filled with compromises. For some, those compromises will likely depend on their usage.
It being niche is not a positive in my opinion. I think it's almost there in terms of being a viable device for a lot of people. But as it is currently I'm not sure. And I still don't buy the argument that it will replace a tablet (particularly an apple tablet) and a mobile phone. Unless all that person does on their tablet is consume content.
Even though a prefer android, an iOS version of this device would be a beast with Apples superior tablet support for apps. Imo, that's the biggest thing holding this phone back besides price.
As for MKBHD, he's never really been a fan of foldables and never really uses them as a driver. Its just not his thing.