The reason I got for whey over getting it from food is because it's good, cheap....
There is no such thing as "cheap" or inexpensive protein source.
All protein is high in price.
And that is coming from someone who made a complete body transformation: I bulked up from 165lbs to 210lbs.
During the ascension I would have my bodyfat level tested annually by using the water immersion process - which is the best way to accurately ascertain bodyfat. Calipers are nowhere near as reliable, ditto for the electrical meter process. Amazingly my bodyfat level stayed the same. My bodyweight slowly went up, but my bodyfat level did not go up. Which meant I built a lot of muscle along with some bulk as opposed to adding all fat (bulk is a combination of fat and muscle - bulk is a good thing for a strength athlete). It took about 4, 5, 6 years to make the transformation. Protein is expensive. And the most expensive protein is the powdered junk sold in a can. That's right. Junk. During my transformation process my main source of protein was milk. Lots of milk. And tuna fish. Lots of tuna fish. If a person needed to know what the ambient temperature was all they have to do was look at me. People say that the junk protein in a can is good for when you're on the road. No it ain't. Tuna fish, milk and cottage cheese is just as easy if not easier to transport. Think about it. With tuna you don't need spoons, cups, packets of protein to transport all you need is a can opener and a fork (note that if you're a Navy SEAL or an Army Ranger you don't need no can opener). And when you're done you toss the can in the garbage. And the cans are small which means they're easy to stash. Milk and cottage cheese is easy to transport in a cooler. During the transformation there were times when I had to run out the door to get to the gym. No problem. After a hard workout I'd hit a convenience store and buy a quart of milk. And then I'd slam it down. That was a good way to saturate my body with nutrients after a hard lifting session. If you're a cubicle worker you don't need to use junk protein in a can since you probably have a fridge at work. LOL just yesterday I saw some guy parked at the gym standing outside of his SUV at the rear bumper going through the multi-step process of mixing a protein drink. What a waste of time. Inefficient. A waste of money. And then when he's done he's gotta go into dishwasher mode and clean his little plastic cup. If he had a pint or a quart of milk all he'd have to do is down it and then toss it in the trash. Who cares if it ain't whey protein. If you think whey will make a big difference in achieving your fitness goals then you've been had. Milk, cottage cheese, and tuna is all you need.
Note that if a lifters goal is to get bigger stronger then many are focusing on the wrong nutrient. Forget about protein or at least minimize it what you need to pay attention to is your CHO intake. Carbs are where it's at. You need to figure out how many grams of CHO you need on a daily basis and then meet that requirement without failure day after day after day. Which is why milk is a fantastic food source for lifters. Because it combines proteins with carbs and that's a one-two punch a hardcore lifter can appreciate. Milk is magic, was for me when I aspired to add size.
And I'll note that I tried different brands of creatine but learned that it was a non-factor and for me a total waste of money. Ingesting pure foods in combination with continually striving to pyramid weights on a regular basis on the basic core exercises (bench press, bent over rows, curls, etc, etc) did the trick for me. I live in San Diego where it's a crime to be indoors with the type of weather we're having. Later.