As I previously noted, the main advantage to spending a night in Himeji would be to permit a very early visit to the castle to avoid the heat of afternoon. There is no air conditioning in the 16th century castle. A later-in-the-day arrival, relaxed afternoon and evening followed by an early morning castle tour and afternoon run to Tokyo keeps you out of the afternoon heat on both days.

If you have already "done" Kyoto earlier in the trip, I see no advantage to scheduling another night there on the way back east. Starting from Kyoto to Tokyo only saves you about 1/2 hour over Himeji-Tokyo.

The Nikko Hotel In Himeji is probably a nicer stay than the ANA in Kyoto for less money.

For another alternative, if you really don't care about the heat, I'd say spend another day on Miyajima, leave early for Tokyo, stop in Himeji on the way, see the castle and have lunch and then make the run all the way to Tokyo - all in one day. YMMV.