The obvious one - it's good for you!
Even our phones and watches are reminding us to get more exercise, with 150 minutes of moderate exercise a week being the minimum recommended. Getting back in the saddle, if only to commute, can easily clock this up. In fact, making it part of your daily journey to and from work (or just a couple of days a week depending on distance) means travel time is used to keep fit and you don’t need to go to the gym! As well as the piece of mind in knowing that you've silenced your smartphones endless demands to get active, you'll be improving your physical and mental health, reducing the risk of obesity and heart disease and increasing your life expectancy.