Super glue for a cup handle 

Yes, we agree that super glues are inflexible and even brittle. JB Clear Weld is a nice 2-part epoxy alternative. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Ff2KpJGPiGQ.html

I agree I wouldn't trust holding a cup of coffee with super glue

This video is an example. The cup went through many subsequent cycles in the dishwasher. Considering the safety concerns of spilling hot liquid, we recommend you use your own judgement about the appropriate use of any object that has been repaired with super glue.

Lots of stuff used effectively in a clinical setting is not stuff you want to be exposed to everyday. Food safe is a relatively high standard. Some products are, some aren't. And there are a variety of cyanoacrylate formulations. Dermabond and Krazy Glue are not necessarily the same stuff.

Yes.

At Repair Café events, I am always cautious about repairing handles on pots, tea kettles, and similar items where a failure could result in a burn. Here, my focus was on the material more than the specific application. I can confirm that I ran the cup through 10 cycles of my dishwasher and it remained more than strong enough to hold its volume of water.

It will hold up until it doesn't

I use my broken cup to put plant in. I accidently broke a perfect cup handle today... im so disappointed. That is now going to be forever another plant holder :(

The original Gorilla Glue is not a cyanoacrylate glue. It is a polyurethane-based glue. Gorilla Glue expands as it cures which makes it unsuitable for most applications. Super glues, as shown in this video, do rely on water vapor in the air as part of the chemistry of the bond they create. However, surfaces should not be moistened. There are accelerators which can be applied to prepare the surface, but those are not discussed here and are not needed for this type of application.