I've done so in the past. It works pretty well, but unless you want to arse around with a mobile app remote and hardwire the network connection, etc. you end up paying as much as you would for a FireTV box when you buy the addons.Just occurred to me I could probably rig a raspberry pi up for similar purposes, could be an interesting little project...
And every now and then you will get SD card corruption and have to reinstall it all.