You and me both. I prefer to learn by doing. But in the context of learning a game system, character creation is not doing. To use an analogy from the computer world, trying to learn a TTRPG system by doing character creation is akin to trying to learn linux by doing bash scripting. Yes, bash scripting and some of the concepts behind it underly a lot of *NIX philosophy, but it's only a very small part of it, and you're better served understanding other pieces first.
This is where the pre-gens are important. They should set some baseline expectations about what a character looks like. If I open CoC and the sample party of characters doesn't have Van Hellsing, Vampire Killer or anyone remotely close, that let's me know that I shouldn't be expecting such a character from the system. Now obviously you can't cover all the possible characters, but a collection of "average" characters should be good enough to get someone started, especially if the rules reference those characters and when you get to character creation could talk about how those characters could have been built differently.These are related. If I know how many points I have to spend, I can calibrate my expectations, rather than reading the skills andwantinggetting my heart set on Fox Mulder, when all I can afford is Gary, the Grocer.