Accepting a tenure track position if I know I won’t stay till tenure
I would ask what the cost of applying is, the expected duration of the process, and the prediction of a similar position opening at your current institution. 

If the cost is effectively zero (perhaps two hours of your time, then another hour to interview), the process taking 6 months, and a cursory conversation with your dept. head and budget, you will lose out if you never apply.

But if you do apply, and you are not offered anything, what would the harm be?

If you receive an offer, would you bet that it would be better (in terms of salary and benefits) than your current role right now?