I have used it to repair torn foil of photographic umbrellas and softboxes, seal light leaks on a repaired darkroom enlarger head, make a reflective pattern for a photo shoot, add a temporary airtight seal on a cracked tube with just two thin layers of tape.

The main issue with the foil tape I have is that it is both thin and very sticky so it can be a pickle to remove.

Not really tested its conductivity yet but for example I realised the other day that I could probably use it to selectively light proof a 3D printed box.