OK, the “11” bit will be heavier than “10”, obviously if you already use 1×10 then adding an extra sprocket to the cassette will make it heavier, just as 1×10 is heavier than 1×9.
And I have NEVER dropped the chain on a MTB (apart from when I ran 1×9 without a chain guide) despite running a triple with no chain guide, despite regular trips to the Lakes/Peaks, Scottish Highlands etc. They have quite a few rocks there which I’m quite fond of riding over. Maybe I’ve been very lucky or maybe the force is strong with me, or maybe putting the chain on the 44t ring before I start descending helps. I honestly don’t know, but I don’t exactly crawl down at walking pace…
TBH I can understand single chain ring setups, but I still don’t get 2×10 as in most cases you lose a 22t granny ring* for a 36t rear sprocket, which makes it heavier and puts the weight on the unsprung rear axle, then you have to make more recovery shifts when you change chainrings as the gap between them is bigger than on a triple.
Anyway, if you’re happy with your gear setup and enjoy your riding then whatever you run is good isn’t it. 😀
*Yes I know you change the size of the other rings as well.