No offense meant to any of my Taco brothers here in the least but I just have to say this. They are the very last thing I would ever do and only in an emergency.
Why??? Because over time they are highly likely to fail and my cause other problems when they do.
How do I know? The hard way of course
They usually cut some of the wires and also cause a poorly supported connection point that can break addition wire over time.
Immediate result from using them is a resistance in the line, long term can be an open circuit which can lead to numerous issues depending on what is passing through them.
Proper butt connections or soldered, either of which can be just as bad if not properly done are far better and at least 90% easier to do correctly.
I am not the smartest guy in the world but I do have some experience in these things, over 40 years