I have noticed a lot of electronics use kapton tape in places where a heat resistant tape isn't necessary. Why is that so? Is it just because it's a good adhesive?
If you go through all the trouble to test and qualify something, like tape: check it doesn't unstick after a few years leaving glue everywhere, doesn't shrink, loosen, harden, or crack even if the product is left in a car baked in direct sunlight for months... then you probably won't feel like re-doing that work for another tape, especially if it saves no money and using a new tape brings new risks of failure for your product.
If you repair old equipment, you'll notice the kapton tapes always look like they're new, but the other types not so much. PVC "electric tape" is one of the worst.
So basically, "if it ain't broke, don't fix it".
Kapton (generically polyimide) is a good material for tape in situations where it does not need to stretch and needs to withstand relatively high temperatures. It does not melt or soften greatly with temperature. It is resistant to most solvents, more so than most tape materials. As an insulator, it has limitations, which is why it is not used as much in aircraft as wire insulation as it once was. As the Wikipedia article states:
Kapton-insulated electrical wiring has been widely used in civil and military aircraft because it is lighter than other insulators and has good insulating and temperature characteristics. However, Kapton insulation ages poorly: an FAA study shows degradation in hot, humid environments, or in the presence of seawater it was found to have very poor resistance to mechanical wear, mainly abrasion within cable harnesses due to aircraft movement. Many aircraft models have had to undergo extensive rewiring modifications—sometimes completely replacing all the Kapton-insulated wiring—because of short circuits caused by the faulty insulation. Kapton-wire degradation and chafing due to vibration and heat has been implicated in multiple crashes of both fixed wing and rotary wing aircraft, with loss of life.
The adhesive on tape is a matter separate from the tape material itself. Typically polyimide tape is available with either silicone or acrylic adhesive. Silicone adhesive has a a higher temperature rating but cannot be used in situations where surface contamination with silicone is a concern (for example on surfaces that will be painted or wire bonded).
Some of the same physical and chemical properties that make silicones attractive, namely a high degree of chemical inertness, thermal stability and resistance to oxidation, make silicone contamination a ubiquitous problem.