It is not intented to wash in revenue, at least they weren't at the beginning.
I read they got founded through huge donations, like Digital Fortess funds.
And as you said they don't want to accept add etc, but let's see what happens if they really bring out some crypto currency.

Btw. If you are using it please be aware that their encryption is not really reliable. There are better messanging app out to protect your pricacy