I think that's debatable. Personally, if I want to hit a function
key, I need to move my hand from the home row to reach for it, and
I need to look at the keyboard to do it....
So hitting `C-x (` is definitely faster for me and requires no
conscious action, quite unlike the function keys. I never use
F3/F4 to define keyboard macros.
In fact, I never quite understood why (some) function keys have
default bindings at all in Emacs. To me, function keys are as
cumbersome as cursor keys, Home/End, or PgUp/PgDn. Not that I
mind, of course, it's just puzzling to me.
Just to contrast the above, I'm a heavy user of the function keys in Emacs. During the years, I have bound F1-F9 to some of my most used commands. There's almost no logic at all in how they are setup but they are hard wired in my brain by now and must be there. Not that I think anyone is interested, but here they are, in order:
F1 - Switch to previous buffer (my most used command/key). This and kill buffer on F5 was inspired by something Alex Schroeder once wrote about on Emacswiki.
F2 - Other window
F3 - Anything (yup, never got around switching to Helm, or Ivy for that matter), mostly with a bunch of super custom sources and commands
F4 - For some reason, this is untouched...
F5 - Kill buffer (no questions if buffer is saved), beeps if the buffer is changed. I use this a lot.
F6 - Strip trailing spaces
F7 - Start kbd macro (this was before F3 was bound to that). I use C-x ( and C-x ) when I don't have my own setup or is using Emacs -Q for some other reason...
F8 - Stop and/or execute kbd macro
F9 - Toggle truncate lines
I can "kind of" touch type, but I mostly do it if I type longer texts like e-mails and such. So leaving the home row is not something that bothers me much. And I make sure to use keyboards that does not require the Fn key to make the function keys to work.
Most of the time I use the cursor/arrow keys instead of C-f, C-b, C-n and C-p, but I use the latter also, when it suits me. Sometimes I also use Home/End and PgUp/PgDn. Sometimes I use the Emacs' keys for the same commands.
So, perhaps what I want to say is that some of us work in some semi-random, semi-structured ways, mixing "pure" Emacs with other styles of interacting with Emacs. But that does not mean we should not strive for good defaults...