Multi-tools are a compromise, but they do a pretty decent job for being such a compact package. Most are not very comfortable, but if space and weight are an issue, they are a great addition to the kit. They may not be the most useful in the outdoors, but the only thing limiting them is usually the imagination of the user. Just about everywhere Ive been
even in deep backcountry, Ive found scrap metal, wire, nails, plastic sheeting/bottles, canvas, etc
plenty of useful items that can be fabricated into functional items and the ubiquitous multi-tool can be a big asset.
I typically dont use the knife blade on my multi-tool, but it is a good back up if needed. I actually like the sheeps-foot blade shape or even a serrated edge for those few tasks that you dont want to abuse your regular folder or fixed bladed edge.
Files and saws are handy, although SAK saws seem a little more functional for me. I really like the wire-stripper/chisel on the Vic Spirit..that would make a great improvised oyster shucker

I do admit I really like the Leatherman Crunch for a compact vice-grips and I have one with me here in Afghanistan.
Carrying a good SAK and a separate pair of pliers isnt a bad idea, especially if it works for you. It's funny, whenever I forget to carry my multi-tool, I usually run into a situation where I need it or somebody else had a need for it. Its a few extra ounces of insurance I dont mind carrying.
ROCK6