That's your opinion, add you have a product to sell.
And that's why most of these apps are pretty useless.
It isn't clear to me why you think they are useless. I find their policy to only publish official trails meritorious. Social trails have ruined perfectly good terrain in Summit and have frequently trespassed on private property to do so.
I find MTB Project the opposite of 'pretty useless'. It has helped me find my way out of a rat's nest of trails, more than once. I also find MTB Project's (admittedly the only app I've used in the field to date) accurate and the most up to date information available.
While I'd like to have a paper map on board that is accurate and easy to use as I don't like relying on technology in the field, they just don't exist for the trail system where I ride. The scale is pretty much useless as trail density is high and the frequency of new trails makes them outdated before they make it off the press.