(I secretly also enjoy thumb holes for their intended purpose + coziness)
In the US in particular, it can be hard to find shirts that aren’t pretty boxy by the time you get sleeves that are long enough for tall folks.
Enter sleeves with thumb holes: they're designed to end halfway down your hand, and for some of us, that extra couple of inches makes them the perfect length (though it can be uncomfortable in the webbing of your thumb if you instinctively put your thumbs through when there isn't actually enough length for that).
I also recommend these for Gardening to keep the sun off your hands, but in that case you actually need the extra length.
(And since you’re here: I find that men’s slim long sleeve shirts at banana republic fit well on sleeve length for moderately tall slender women—I’m just shy of 5’9” and my men’s XXS flannel is great, though a touch tight when all buttoned up. This approach also solves the other issue I encounter which is that women’s tops (even workwear like Carhartt!) are often cropped to be too short for my torso 😒)