This article says it was literally the first operation of its kind and even though it seemingly was quite successful, they only reached a couple thousand users

This article says it was literally the first operation of its kind and even though it seemingly was quite successful, they only reached a couple thousand users despite aggressively promoting it on the black market and even by using undercover agents. If any intelligence service had the capability of building a 100M+ user app like Protonmail, they would never have to ask congress for money again, because they could basically print it themselves.