Well, these foam tips don’t block completely anyway (and neither do most other IEM tips/buds/whatevers, custom-molded inserts being the exception of course) but the better the seal is, the lower you can set the volume, still hear your audio and your ambience and not damage your hearing (or risk your life) in the process. I have been using these exact foam tips for a while now. When I go to work by bike in a very busy city in the mornings I set the volume quite low so I can hear what’s going on around me but still get good sound. If I’m just on foot, I can set the volume a little higher and have even better sound.
For me, it’s the best of both worlds. However, that is probably, like most other things, a case of personal preference.
