Ive experienced this service several times southbound from Edinburgh. It does sound odd, but there is a certain sense to it - particularly when the food options are reasonably substantial.
I agree that it makes sense if it's a GWR restaurant style service, and all those partaking of it are doing so at broadly the same time on broadly the same journey.
However, I travel mostly for work, and when I travel by train, I work when I travel. The catering is not a key part of the journey, mostly because (and I appreciate that this is very subjective) I find the vast majority of the First Class catering to be pretty poor.
The oohs and aahs for the freebies seem always to be from hen parties and holidaymakers. Breakfast is the most reliable service, I find.
Hitherto, I would often decline the food, which apart from anything else, gets in the way of working, but at least I could have a coffee pretty much as-and-when, with fairly regular passes up the train - and maybe a cake or a biscuit. That's become more difficult on many services now, unless I can charm the crew to put a pot on (or more likely to bring the crew pot along).
If I get on an 11am service and start working, however, I don't want the first service offer to be wines, beers and spirits, nor to eat 'lunch' at 11:15, nor to have to wait until 11:30 for a cup of coffee.
For me, it just doesn't work.