"Custom-" vs "customize-"

[Drew Adams]

There is this comment in cus-edit.el:

;; No commands should have names starting with `custom-' because
;; that interferes with completion.  Use `customize-' for commands
;; that the user will run with M-x, and `Custom-' for interactive commands.

Of course "interactive commands" is redundant, and doesn't in any way
distinguish this case from "commands that the user will run with M-x".

Ignoring that, I imagine that what is meant is this:

1. `custom-' is for non-interactive functions (non-commands).
2. `Custom-' is for commands that are bound to key sequences.
3. `customize' is for commands that are not bound to key sequences.

If that's what the convention means, then I don't understand #2 and #3. Why
distinguish names based on whether or not a command is bound?

And even if that were a good idea, the convention is confusing because #1
and #2 are closer than #2 and #3 - why associate (and therefore confuse) #1
and #2?

Unless I'm missing something, I suggest that #2 be eliminated in favor of #3
for all commands. If this breaks old code, then we can create aliases and
deprecate their names.