Carried one for years and used it once so far.
Carried one for years and rarely used it on my own chains, but have fixed chains for 3 or 4 other riders. I have also watched fellow riders fix chains using their own chain tools.
A broken chain is a showstopper, so I consider the tool essential.
I lost a jockey wheel on a recent ride and had to take my chain off to be able to 'scoot' my bike 4 miles to home. That confirmed that the tool is useful, and that I do not enjoy being miles from home and not being able to ride the bike because of transmission problems.
It is your choice but I say 'carry'.
Put it this way, I doubt that you will ever find yourself regretting carrying an unused tool, but if you ever do break a chain at a bad time, you will remember this thread and think how you should have bought one!