It's kinda like asking "Is it worth being rich?". By reaching top hashtags (Not the general hashtags that every spam account uses, e.g #love #instapic etc. but hashtags specific to your niche) You gain free exposure for your images, which will always result in more followers/likes. How much it helps depends on the specific post and the niche of course.
Please tell me a niche or a few where this is valid. Seems strange if, e.g. all tattoo people want to follow accounts reaching top of hashtags for tattoo, when this is not happening in other niches.