Sometimes you're just curious if you'd notice the difference or if you like it. Just because you're not discerning doesn't mean you won't notice differences or have preferences this time.

I'm not a discerning drinker, but sometimes I'll still order a fancier beer or glass of wine, because... why not? I don't do it often, so I don't mind dropping some extra bucks, and sometimes I experience something new and interesting.

In this case, I would take discerning to mean noticing smaller details that other people might notice. That doesn't preclude having preferences.

Also, $5 for a pound doesn't really seem like a lot of money. Pasta is cheap in general.

They greatly enjoyed the pasta. They didn’t say they “greatly enjoyed spending so much more money”.

I didn't notice the price and don't really care. Either way it's much cheaper than eating out and I'm happy to pay a bit more in absolute terms for better food. (E.g., even if the relative difference is a 100% price increase, it's still a couple of bucks for a big bag of pasta).

I like the shape and the texture, and it does seem to hold a lot of sauce. By "not particularly discerning" I meant that I'm not a pasta expert and I might well not notice something like it not cooking perfectly evenly, and I wouldn't really know whether there being other equivalent pastas out there that have similar or better features. I'm just familiar with the usual stuff (spaghetti, macaroni, ravioli etc.).