[Lonthego]

Hakone is mainly known for Mt Fuji and its onsens..since you like onsens it may be worth it. There are a few other things to do, such as hiking in areas with volcanic fissures.

It really depends what else you are doing on your trip, because Hakone is pretty out of the way, thus the whole thing will take up an entire day or more if you decide to stay. If you are seeing some other areas with an abundance of nature on your tour, then I say you can skip it, but if you are only running around concrete jungles then Hakone might be nice.