Your point is quite valid, but situations vary. I would say that MTs are handy and useful,but cannot, nor should not, do everything. Just today, I had to clean the strainer on our kitchen faucet. I had my Skeletool in my pocket and tried that - way too small and the fitting was really stuck tight. So over to the toolbox and got a channellock pliers that made the task easy.

It's just that a lot of times, you only need to tighten a screw, or adjust a fitting - something very basic and trivial. If you don't have a tool handy, the most lengthy part of the process can be finding the screwdriver, or whatever you need. For most of the stuff I encounter, the MT gets the job done very capably.

Years ago I was on the beach and a dinghy was bring people and supplies in to the shore. During one of the trips, the bow line of the dinghy got tangled in the propeller of the dinghy (big mistake - the bow line should be short enough that entanglement is impossible). The dinghy operator didn't have a knife, nor did anyone else on the shore - except me! We swam my PST out to the dinghy, which was drifting slowly toward some rocks, and freed the prop. I was surprised that i was the only one of about four people who had any kind of a cutting instrument available....