I have done half day in Hakone area also, but I have been to Hakone many times living in Tokyo. Hence, I did not feel as half day trip as waste of time or missed out on a lot of other things. Because I have been to Hakone many times I did not feel as half day trip as stepping my foot into the area simply to claim I have been to Hakone, nor I felt as I did not see or experience anything significant about Hakone.

However, on previous posts OP has mentioned five nights stay in Japan. Sounds like Tokyo Disneyland is must for OP. If OP wants to spend more than a day at Tokyo Disneyland then adding Kyoto and Hakone, have to start wonder why want to squeeze that many things in five days. OP is asking now about arcades in Tokyo so that also suggests OP wants to spend some time in Tokyo. Overall, looks as OP wants to do Tokyo Disneyland, Tokyo, Kyoto and Hakone all in five days trip. Fifth day seems to be the day OP fly back to the U.S., so practically want to do all those in 4.5 days.