> making me more valuable in the long run so eventually I can make more money

Sorry to burst your bubble, but the "more money" from experience gained while taking a paycut will pale in comparison to "more money" from the number of years you state on your cv and dollar value of your last salary.

In perhaps clearer words, taking a paycut for career growth will most likely just prohibit your potential future salaries regardless of how much technical experience you gained.

This of course all changes considerably when you're talking founding/early employee where minimum wage is a real possibility..