I understand the crumb concern, but you’re not really “laying down” if you have sufficient pillows behind you.
I think it should be lying down, although I’m not sure which one I say when I’m not being careful.
I tried breakfast and other meals in bed once or twice, and I don’t care for it for the reasons stated upthread. I watch TV from the couch in the evening, and I’ll occasionally eat dinner or snack there, but I don’t like the potential messiness. I don’t even like drinking there.
I have asked my wife to make me breakfast in bed more than once but she always refused and insisted that she would only make the breakfast in the kitchen and then serve it to me in bed. She wasn’t exactly thrilled with other parts of the request but didn’t rule them out either.
I sit up to eat breakfast in bed. I usually sit up to read in bed, too.
I lost 50 lbs. in 6 months thanks to hospital food.