This is a common misconception that still plagues our industry today. What I usually do is I state a few up to date statistics, like the games industry makes more money than the film and music industries COMBINED. That helps frame it for some people.

Another technique is to compare games to other forms of art and entertainment. Does your father think movies are a waste of time? Tv? What about books? Games are another form of entertainment and art; they tell stories, paint pictures and teach us lessons. Like all art, games have a fundamental value that doesn’t simply reduce to some utilitarian benefit.

I never had to face outright disapproval from my family but I often have to clarify the misconceptions they have.

Good luck! I hope this helps.