With my first answer on StackExchange, I try to explain the core concepts of MATT with as little technicalities as I could.
Not quite an explanation for your grandma yet, unless you have an exceptionally cool grandma.
The problem with drivechains is that while they enable "everything", we want some of the features on native L1 bitcoin.
For example, vaults.
A powerful enough covenant is better: you can get the programmability of drivechains on layer 2s, but also some useful layer 1 features.
Released an early version 2.2.0-alpha of the Ledger Bitcoin Testnet app.
It supports miniscript on taproot.
We're only halfway in #miniscript year!
Have fun! 🥕