Until you do something that doesn't work? What kind of argument is that? Just 1. turn it on 2. hold down the power button to connect and 3. pair the final device up to it, no password needed. That's a 10 second process.
The example given was bluetooth being great because it works well in the OP's car car.
One device.
I have tried bluetooth speakers in my flat on. Works fine on two Linux machines. Doesn't work at all on the other. Connects to the windows machine but isn't actually usable as the music skips so frequently. If I have only tried it on the first device I may have came to the same conclusion as you. Fact is bluetooth isn't especially reliable.