Crypsis is designed to be the 'go to' universal breaker of the core set. It wasn't made to break every ICE you encounter. It was meant to break that ICE you couldn't break with the core set breakers. It was mainly intended to complement the Anarch fixed strength breakers though and while it lost some of that appeal with recent expansions there are still a few reasons why you'd want to include it in your deck.
The most important thing about Crypsis is that it's a virus. This means two things. It can be tutored with Djinn and it complements Noise's ability. In fact, before Hades Shard was released Crypsis was the tool to make sure you got into the Archives for your points in a Noise deck. Because Crypsis can be tutored it was also the standard Anarch solution for when the corp thought was secure enough to start scring. The usual surprise play was to find it with Djinn, install (hopefully getting a free virus counter from Grimoire, click for virus otherwise) and Stimhack away for great justice at that Agenda.
The thing about AI breakers is that they are all designed with big limitations you have to work around so that they're not really feasible to be your only breaker. Crypsis requires virus counters to stay on the table which you have to put there in advance or you might end up not having enough clicks to keep it after the run. However, even though it uses virus counters it's not really a good synergy with Incubator or Hivemind. If you're running the 'virus farm' toolkit and need an AI breaker Darwin might be a better choice as it's a more efficient use of that precious Hivemind.
Despite all that Crypsis still remains the most straightforward AI breaker (next to Overmind) and having one on the table can keep the corp from brazenly scoring an agenda behind that one ice you can't find a breaker for. As long as you can afford it at least.