What i find is that most people don't know how to use wire nuts. They twist the wire together then put the wire nut on it and spin it. This isn't how they are designed to be used and often leads to a weak or loose connection. Put the wire in straight and push it as far as it will go and then use the wire nut to twist the wires together and lock them into place.

Butt splices might be good when done perfectly but there is a lot of room for error. The last time i used them was when i was on the very top of an 8' ladder and i had a butt splice loaded into my crimpers. I put the wire in and before i had it crimped i swayed a little and it slid off the wire. With wire nuts you don't need a tool, you don't have to worry about cutting through the butt splice or the speaker wire. And if you ever need to service the splice/connection you don't have to cut and strip again.

I used them for 10 years but never again. These days i use wagos. If wagos vanished today i would go back to wire nuts.