You don't have to "page through a giant iPhone screen", you can type and select. I used to use it all the time, without ever reaching for the mouse to do so.
Launchpad also let you change the order of app icons and group them into pages and folders; I don't think the new system lets you do any of these things.
Launchpad was focussed on a single task: launching an app. If I need to launch an app, I know I need to 99.9% of the time (I'm hedging; it's probably 100%), so there's no benefit showing me documents, web pages, and god-knows-what-else at the same time.
I nearly forgot: while I was testing Tahoe, I had a situation in which some apps just did not show up when I typed. They were in the list, they just got filtered out incorrectly. I've no idea if this was a bug or not; I'll see when I upgrade to the final release.
