I have a proxmox hassio VM with 2gb ram and it runs everything smart in my house. The main purpose would be for automations IMO. Like when my phone chargers at night the house lights, TVs locks all shut down and the cameras go into alerting mode. Home assistant is amazing since you don’t have to have 5 apps to control stuff and your data is completely private unlike when using Google home etc. When buying IOT devices I would say stick with zigbee, zwave and only buy WiFi stuff if it works locally without having to have internet wccess.