I just moved into a house with my friend and he gave me full reign to smart home the house. Every light has an Innr Zigbee bulb, which are great for having colors during parties and color temperature throughout the day (Adaptive Lighting in HACS), as well as motion controls in the hallway (which has a broken 2 way switch) and kitchen. The front porch light turns on when I come home if I'm on foot, and the back porch light comes on if I'm driving. The lights in the living room turn down if something's playing and it pauses if I leave the room. We've got an old android tablet I stole from the trash on the kitchen wall for a shopping list as well as an overview of the house. They washer and dryer have vibration sensors so we get an alert on our Google homes when our load is finished (we're both forgetful as fuck). I had an extra contact sensor left over from the doors that I put on the mailbox, so we get a nice AOL "you've got mail" when the mailman comes.
Frankly I don't know how I survived without automation. I forget things so much less now.
Definitely not as big as it used to be. Lineage, Graphene, and Pixel Experience are just about the only players left. Graphene doesn't officially support anything other than pixels actively supported by Google though.