Hi,

I feel ( last visit in May and another visit in December) that the evening offerings at the Conrad whilst nice are more of canape size helpings.
There were a couple of hot items in warming trays and the rest of the canapes were in glass cups ( almost like single servings) I ate at Cerise as it was my birthday on my last visit.
Its been a couple of years since my visit to Hilton Tokyo but iirc the evening offerings were reasonable
Afternoon tea at the Conrad Tokyo EL was reasonable

After a full day's sightseeing, some days you do not feel like going out
I was at Conrad Osaka in mid April and there the evening snacks could easily do as a light dinner ( the offerings at Conrad tokyo changed daily so one day you might feel ok with the options and other days not so much)

My current plan in December is to sightsee the gardens after breakfast then back for Afternoon tea/pool time then out in the evening for seeing the winter illuminations ( will probably have dinner outside the hotel)
Regards

TBS