Do you like the effect the little silk in your soap gives? I guess there's a difference between "silky" and "slip"... you can have both maybe.
Just make sure you use a hand-sized mold with lots of corners so that it doesn't continually slip out of your hand in the shower. I hate bending down to pick it up off the floor. Must be those prison movies... Hahaha
Honestly (I might get flamed for this), I never felt that silk made enough difference in my soap to justify the effort trying to dissolve it in my lye water. But it just may be my insensitivity to such things. If you're a seller, it might get label appeal - except to vegans. If you like it, go for it!
I've kinda gone full-circle in my soap making. I started with a simple recipe with no additives, then gradually got into adding and experimenting with all kinds of crazy things (think pureed mango! LOL). Then that faze gradually passed, and now I'm pretty much back to basic oils and EOs. I still do natural infusions of annetto seeds, juniper, cedar, and such... and a little clays only for color. I don't like the way bentonite feels against my skin in the shower, but as an additive in shaving soap I think it's great. But experiment and see what you like.