I use it to over mark cables, and to finish off when using harness tape, to pull cables through, and to insulate within an enclosure, where your not ready to connect a circuit turning the wire over on its self and a little insulation tape ensures it does not touch live parts, insulation tape can be removed without a tool, however inside and enclosure which requires a tool there is no problem.
There is even a one inch strip of insulation tape on my car door contacts to stop it auto locking when closed.
Using insulation tape instead of an enclosure is clearly wrong, but wrapping insulation tape around the cable joint to stop it leaking while the epoxy resin cures is no problem. A role of white is great for temporary labels, and green/yellow very good to identify earth's, brown over the blue wire in a lighting circuit is far less likely to fall off than a brown sleeve. I do use sleeving but for over marking I see no problem.
I have used it when I have not got the correct item, round my bikes handle bars so the bike light is firm, there would have been spacers when new.
One problem I find is where used to protect cables, you simply don't know is it there to repair or protect, only way to find out is to remove.