I like the idea a lot, any effort to spend more time with loved ones and off the phone is a noble pursuit. I think one thing that could add to this and help to habitualize it - would be ongoing statistics.

Something like..

- 3.8 days dedicated since you began in March

- 4.5 hours dedicated so far this week

- perhaps even being able to set up weekly goals could work

You are already using localstorage, so expanding on that sticks to your no account/analytics ethos.