I’m going to say yes. What about if it gets lost?
However, having said that, I know cats can be scoundrels! According to studies, up to 75% of cats will wear collars if they’re introduced to them gradually for short periods at a time (http://www.huffingtonpost.com/dr-karen-becker/cat-collar_b_1470615.html). Sometimes, their tendency to scamper through bushes and up trees does mean collars can sometimes break or come loose, and the cat scratching at the collar is a commonly reported problem.
So, yes to wearing collars, but also yes to microchipping. There’s no way that can get caught on some brambly bush whilst the cat stalks its prey. I’d be gutted to loose a pet and not have any way of getting it back. Apparently only 2% of lost cats in the US are ever returned to their owners.
I’m going to have to stop here before I well up/book plane tickets to the US to go and get all the cats….!