Maybe we should define our terms. I say savings is anything that accrues interest. If my 401(k) is invested in instruments that accrue interest, why wouldn't that be considered savings? Can I not borrow against my 401(k)?
401K is fine, but it's got serious strings attached. You can call it "retirement savings", but it's not what I think of as savings. It's an investment that is at risk, and that has strings attached designed to force you to not touch it til you reach a certain age. So for me, savings means low or no risk, and no strings. Of course you don't get a great return; that's not the point of savings, the way I use the term. I think you need to do all of it: invest and save.