How are they? Just like a Mars Bar? I recently saw one costing £3.29 at a cycling fare; and I understand you can get them cheaper and can probably order a box online for much cheaper, but the unit price is still eyewatering for what we humans call 'food.' If I am on the bike already how much protein do I really need during a ride, and if I am off the bike why not have a juicy steak dinner? I've seen Pros necking tiny cans of Coke on the go for sugar, but who is muscle building? I can't see how these are effective or economic for anyone. Have you bought one?
I could get a kilo of whey powder for that. It is bad enough that Mars Bars in shops have shrunk so much they are now like the old fun sized minis (I used to string out until February 1986.)