I think others have covered the main points, but I found it hard going for 1 device (ie a Ras Pi, VM, etc), but then it was effortless when I wanted to add a 2nd (or more…), so at first pick the sensible uses, then consider ansible for that one-off device a little later…
I like a few specific utils (tmux, nmon, htop) on all my devices: ansible script
I want to update all the Ras Pis in the house: ansible script