A permanent Tinkering at the expense of 1 MU and 2. The MU cost is the real problem, in terms of credits Egret will pay for itself if you can break ice more cheaply using a different breakers.
Looking at this card all I can really think of is Study Guide. Slap a few Egrets on non-code-gate ice in front of R&D and charge up the study guide. You then have very cheap access to R&D. Also works well in combination with Kit's ability as that lets you avoid slapping an Egret on the outermost piece of ice if you only need to make one run per turn.
Egret is very much a shaper solution: instead of making better keys let's change the lock. In a way it's a shaper's Parasite. Not destructive but still effective.