Improving the situation: deep insertion improves tonality and bass presence. While I don't typically do this with most products, these seem to one of a few that improve doing so. The SA6 is one of the other earphones I've run that seem to necessitate doing so to sound correct. I'm now using some Klipsch oval biflanges to do so, and the earphone housing limits how far you can insert them.
What does deep insertion offer over shallow insertion, a warming of tonality and improved bass presence.
I'm typically not a fan of this due to comfort. It's often hard to find a tip that lets you do this comfortably.
There is some earphone vibration though with this setup that limits it a little bit. Some transparency and energy is lost from it. Your attention goes to the earphone instead of the music. Some of the bass energy is lost, and you lose some of that energy. I can hold my finger to the earphone and fix it, but I'd prefer a tip choice that doesn't require it. When the idea of low frequency presence like on strings, this is where some of that presence is lost. Being a very light housing also lets it move more freely. Chances are some mass loading could help the cause, at the expense of a little bit of comfort though, but it would translate into more sound energy on the low end and improved transparency.