When I retired from my professional career, I promised myself that I would never again carry a laptop computer through an airport. So when I took on a retirement job that required that I maintain e-mail communications with a large number of people, I bought myself an iPod Touch - basically an iPhone without the telephone function. That worked fine, but my fat fingers didn't work well on the small screen/keyboard, so I made a stylus using a PSI kit (with a brass tube). That was a great combination.
Several years later, I upgraded to an iPhone, but I didn't migrate my stylus to that new technology. I just did a simple test - the stylus does work on the iPhone, but I can more quickly use my fingers. I also tested that stylus on my wife's iPad, and it also worked although with the larger screen, a stylus is not required.