By crappy body guards, do you mean... other high level characters that don't turn out well?
It's certainly worth it to use Frederick to clear objectives (killing enemies headed for treasure, thinning enemy ranks, etc) faster and he provides excellent stat boosts as a pair-up buddy. Early game, nobody can do Fred's job as well as Fred.
When people are on par with him though, his starting stats (bases) are not so impressive. The game has grinding and Frederick's classes and skills are usable if you want to make him viable through grinding. Because Frederick is a gen 1 character, gen 1 characters suffer viability issues more dramatically if you are indeed choosing to grind.
I found that if you reclass him into a Wyvern Rider as soon as you can, he makes for a good unit.
PEMN but I did this and it was pretty dire. His high internal level makes him level slowly and his unimpressive (for his level) bases really held him back.