Depends what skill your doing. I would for crafting etc. but if I were to fish, I wouldn't spend ages getting the SC harpoon because in my opinion there is no point. I'd only get the double xp tools to save cash.
You can actually save time doing these. If it costs you 100m but with the rewards it'll cost 50m. You're not only saving that 50m but also that time to gather the other 50m.