I consider cycling quite beneficial and healthy, as it increases blood flow, breathing rate and thus flow of nutrients and oxygen into all parts of body, including soft tissues in your wrists. It means that they can regenerate faster.

However, there are some risks specific to cycling related to vibrations during ride. They transfer from handles to your hands which can make your RSI worse. I learned this the hard way, so if you want to avoid this, make sure that:

1. Have a high quality (ideally new) and wide tires. They are much softer and prevent a loads of vibrations
   I was using cheap bike with old tires. After replacing them with new I felt immediate improvement. I also do not like road bikes as their tyres are very thin and reduce vibrations very little
2. Purchase foam cover for your handles
   These covers are hollow cylinders from some soft material and you just put them on your handles
3. Use additional pair of vertical handles, attached to the standard one on both ends
   Do not forget to put foam cover on these too

Also, I try to avoid long down-hill rides where you need to hold breaks long time as this put extra strain on your hands and wrists. In such cases I make several breaks in the middle of the hill to split the load.