You’re in for a good time with that thing. Its also great if you want to do more with it as you feel comfortable doing.
As for my impulsive buy? Id say the same thing as yours, when the steam deck came out I immediately pre ordered it. I had been waiting for a good PC handheld experience for a very long time and Valve were the ones to show up unlike the very bad GPD Win I used a couple years prior.
The only thing I knew about it was that it was going to use linux so while I was waiting I started to learn about it and actually use it on my main PC over windows and I have never looked back since.
This was definitely done to spite GrayJay no doubt about it since they clearly state in the app to download the version from the website rather than the play version.