At least for me, I had to try using it three separate times over the past decade for its killer features to sink in and my usage to finally stick. If my experience is common, it would explain a lot of lag in adoption.
I went through the same cycle and it did finally "click" as well as mature. I now reach for it first for everything. I think the best gateway drug to actually _wanting_ to use it is nix-shebang scripts. If you get into the habit of writing your scripts with that, you will begin to really yearn for nix in other areas.