Even if it would just deliver 1 or even just 10 meter resolution, I would imagine the high revisit frequency would make it commercially valuable, and potentially also provide some value to military/intelligence groups because it would make it harder to hide activity through careful timing and the data would come with fewer secrecy requirements.

And I have no clue what is doable with SAR, but I'd imagine multiple satellites following each other would enable some interesting features, as it essentially gives you a giant antenna.