Yeah I think in most instances, it's not a good idea to convince someone to get a "practice" pet or a different pet than the one they want, because they will not be attached to the animal in the same way. If you want a cherry popsicle and some hands you grape, you maybe be okay with it, but it's not what you wanted, so there will always be this little part of you that's disappointed. With a pet, that can lead to disinterest and even eventual resentment/neglect, especially with a young kid that hasn't developed the kind of ability to power through set backs the way an adult would have had the opportunity to.
BUT! It's also important a person has a good idea of the REALITY of what they're getting into before getting a pet, otherwise you'll see the same thing happen because they fell in love with a romanticized idea. That's why research is important, but ALSO why it's important for a kid to have adult direction and guidance. An 8 year old might not be thinking about the fact that budgies can be NOISY when doing research about the other care aspects, but an adult that knows them can point out "hey, these birds are very vocal, they will be loud all day as part of their behavior, because that's how they communicate in the wild. They're very social and will need someone to "talk" to constantly, are you sure you can deal with that?"