What's wrong with that? This is a post to show users that other people are paying for it (social proof) and that the project is developing well, similar to other projects sharing how many contributions or first time pull requests they got this month. That doesn't mean that you have to show everyones salary, how much the lunch in the office is costing and include a raw export of their bookkeeping setup.
There's room for both.
The accompanying blog post says "The one thing you couldn't see was how well Ente is doing as a business. Now you can."
To the parent commenter's point, we don't have enough information to know if that's true.
EDIT: the founder is on this thread (https://news.ycombinator.com/item?id=48933905) providing more info and explains that adding expenses on would be too burdensome.
I’ll also add that private companies don’t have to do this at all.
So, yes, by comparison, this is very open.
Is it marketing material? Also yes. People who are considering using a small scale alternative to tech giant products will probably look at this and say “oh, this product has some traction, and this isn’t a fly by night business.”