I'm close to a TB myself. For me, I'm a bit of a "completionist" and can't stand having just 2 or 3 tracks from an entire album. Every track I have is accompanied by the rest of the album it was released on.
Sure, it means there are some duplicates at times, but it's worth it to me.
My favorite use case for MASS is my desktop PC, in our bedroom, has a decent 5.1 sound system, and is running squeezelite.
I have an alarm automation that starts playing from the random 500 playlist.
When my phone connects to my car's Bluetooth, it transfers the queue to my phone, which is running snapcast on a VPN.
When my phone disconnects from my Bluetooth, and I am at home, it transfers any queue from my phone back to my desktop.
If I'm not at home it just stops the music, otherwise it'll start playing through the phone speakers.
While at work, I'll use Ultrasonic rather than music assistant, because my data inside my work area is sporadic, and not conducive to a good musical experience with how MASS streams.