Is it worth going to Instructor School if you don't have plans on teaching at any school house?

Yes, go. Good way to get a teaching/instructor gig, especially for a government contract

There are really no bad courses in the Army to take. I took the Instructor course as an E4 in the Army and though the SQI isn't on my ERB (hooray National Guard) it helped me while instructing junior Soldiers down the road. The instructor course actually lays out a very solid, science proven, practicum for teaching new subjects to new people. Every single instructor of every single school has to certify in it, and every single school follows its training model. It has reliable and proven results, so go for it

1: Never turn down a school
2: Unless its an illegal order, never say no, but do say what it will take, cost or need to say yes.
3:Never argue with the boss in public, but by all means tell him he is mistaken, wrong, misunderstanding, or a flipping moron as needed in privet
4: Few will remember how much effort you put into making a mission work, but everyone will remember your failure...what do you want to be remembered for?
5: Never turn down a school

It worked for me