It does matter over a long enough time span, but otherwise I agree - don't get into resistance training for the extra potential calorie burn/metabolism boost, it's a quick way to burn out. Get into it for the numerous health benefits that resistance training brings, the effects of which get especially important as you get older.

You can lose upwards of 3% of muscle pass per year at 60+, and this process can start as early as 30-35 years old. It gets harder and harder to build muscle as you age too, so the more you can build and maintain early on in your life, the better off you'll be in old age.

Other than aesthetic goals, that's most of what got me into weightlifting. I'd prefer not to be so frail when I'm older and want to maintain my independence as long as possible. Not to mention, being strong just makes general day-to-day tasks easier.