and the "don't stop pedaling" thing is so you don't stall, and while intuitively reasonable, not always the easiest thing to execute!

I don't MTB very often (scares the bejeesus out of me), but I know that feeling of pedaling up hill, then seeing some obstacle, thinking "OMG, I am going so slowly, there is no way I am going to make it over that rock, root, etc" so I stop pedaling for a fraction of second to think about what I want to do, and then stall. I am actually pretty strong on hills (power to weight is my friend) and so can usually get it going again from a stall without unclipping, but it isn't easy. So "just keep pedaling" is great advice!