Interesting aside: the “Globe” key on an iPad keyboard-folio (the one that opens the IME chooser) has some but not all of the properties of an Fn key. Globe+Left and Globe+Right work as PgUp/PgDn, but Globe+Up and Globe+Down do not work as Home/End. (Or maybe they do, but Home/End just aren’t bound in any app I’ve tested? I don’t want to write+deploy an iOS keysym tester just to find this out...)
You can also plug in arbitrary USB keyboards, or pair arbitrary Bluetooth keyboards, to a Mac, and the Home/End keys on those will also do what you'd expect.
Apple just doesn't bother to put Home/End/PgUp/PgDn keys on their laptops — presumably because they find that people don't need them very often; and that, when the keyboard's size is already constrained, people get more value out of fewer, larger keys (while requiring key-chords for some things) vs. more, smaller keys.
No, they don't. I expect pressing Home to go to the beginning of the line I am on, and I have to hit Command-Left for that, and Home does nothing of value.
e.g. ^A ^K to clear an input line
I use Ctrl-A and Ctrl-E all the time.
cmd-left/cmd-right go to beginning/end of the line.
It seems Word for Mac supports cmd-left/right but not cmd-up/down. Word also supports fn-left (home) and fn-right (end), and fn-opt-left does like ctrl+home on Windows.
Bonus: also try Ctrl+E (and Ctrl+A) in text fields, or on the command-line.
(Both of these carry over to iOS, if you’re curious. I just tested them with the iPad keyboard-folio thing.)