Proximic doesn't crawl for Adsense. They crawl for ads which Proximic shows through Adsense. So if a big chunk of your Adsense revenue comes through their affiliate ad networks and Proximic is one of the larger players on your site, it may impact earnings.
One site I have I don't block them, it impacts earnings. On another site I do block them because it doesn't impact earnings. The only way to know is to test on your site.