Sorry to be blunt, but you are being delusional. Or incredibly pretentious. Or both. That strategy is never going to fly, ever!
Do you seriously think that in order to be able to use Affinity Photo effectively, we are supposed to want to use your DAM? To like it? To change all our habits? Our workflow?
Do you plan to support all the file formats supported collectively by all the DAMs we currently use?
Do you seriously expect us to keep our pictures in a file format only known to a tiny company who might not be there in 5 years, who strongly commits to not document the format and makes claims it is very difficult to document and understand?
At the very least, you should offer a choice of default format between your own, tif and psd, and all 3 should support the same level of editability. The ease of saving should be the same whatever the default format the user chooses.
I bought your product because I decided to make a $40 bet on something that looks very promising. Your attitude in this thread appears to make it a losing bet.