I think mBTC should be called a bit.

Milli BTC = 1/1000 of a BTC or 100,000 sats.

A tank of gas would be 1-2 bits.

Taking your family out for dinner?

1-2 bits

Groceries?

1-6 bits.

People have heard of bits. Its an easier unit to rap your head around for new people.

It's a shame that mBTC doesn't catch on. It's the most practical.

If 1 BTC = $30,000.... then 1 mBTC = $30.