Nice. Since there's no way I'm going to put a multi-billion-dollar company's 'smart' speaker in my apartment, I've been wanting to build something offline like this inside an old dial telephone (like a red Bat phone) which only listens to your commands when you pick up the handset. ;)
I like the idea. I'm shocked that a ras pi has enough cpu power to make this work.
My Dad used to use voice typing on his old Pentium II laptop in the late 90s. It's doable, although a lot less reliable than the ones nowadays.