Yes, that is one of the factors for where this thread originated, talking with various folks in a different thread about the best value Garmin on the market.
I have never been keen on multi-tools, whether it be that it gets lost, or broken or simply that they tend to do all jobs but none of them particularly well.
But, when it comes to electronics then other facets appear; in this case, Android seems to be a really well regarded "multi-tool" (i.e. loads of apps) operating system. Time will tell.
Even though the OP doesn't like Garmin (I think primarily for its' software, but he can speak more on that) he still carries quite a few tools in his bag - (see earlier posts for his) = smartphone, laptop and, yes, a Garmin!

But, one gets the sense that smartphones are in their infancy for developments regarding navigation apps/software, and who knows where they are going in this regard.

Hardware ruggedness; Yep, needs more development, but I would think that will happen - it did for standard mobile phones with rugged models aimed at farmers (at least one of the vids in an earlier link here is from Farmers Weekly, or some similarly titled source), builders, climbers etc etc.
For the farming video, they drive a tractor and a 4x4 over the various phones on test with no significant distress to the phones.

There are smartphones that don't make calls??

ps Don't have a smartphone, nor a Garmin, but I do have a Tom Tom (but no one talks about them!!)

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Dave