Personally I am very happy with Welcome Amenities which are somewhat long lasting and do not need to be consumed in a day or two. If flying, then small bottles if bottles are involved.
The three bottles of honey and bar of soap above would be useful for me.
Some useful things cannot be photographed and are not really Amenities.
I have been struggling with (outsourced) laundry service in the little Mercure I am using for a long stay. But now they have assigned an extremely competent Housekeeping Supervisor to pick up and deliver my laundry perfectly after a lot of hassles and mistakes with the previous standard service. This makes my life here much easier.
One week ago at Christmas (while still Platinum, not yet Diamond) the hotel restaurant delivered a Christmas Eve dinner and then a Christmas Day dinner to my room. Then a couple of days later received a Happy New Year piece of cake and message.
It is still my guess that the value of Diamond will be in (photographed) surprises appropriate to brand standards and room rates, and (non-photographed) better/smoother service when things go wrong ... non posting of points or whatever.
By the way, I was very impressed to read that Amy was able to fix incorrect posting of points by four hotels for one FTer. That is very useful to know. Well done, Amy !