If you are in a competition or collective mileage deal and you have to use Strava as a method to record the miles then I can understand it. But otherwise I can't see any reason especially for a regular daily commute that doesn't vary. I don't like using the connected phone apps as they are a big battery drain on the phone, which is a bad thing if you are on a long ride and you're 30 miles out and you have an emergency.

I use a Garmin 200 and have a mount on all my bikes. Easy to remember to turn it on and off, weather proof, and no fuss. So no matter what bike or where I'm riding my miles get recorded and then saved when I charge it.