It's not important in the sense as it does not impair daily work. It is more the appearance of a tool spilling debug information which gives a somewhat unprofessional look. That's about it.

Am Di., 14. Jan. 2025 um 14:01 Uhr schrieb Eli Zaretskii <eliz@gnu.org>:
> From: Johann Höchtl <johann.hoechtl@gmail.com>
> Date: Tue, 14 Jan 2025 08:14:08 +0100
>
> I find the load messages during startup, caused by (custom-load-symbol 'foo) disturbing.
>
> That is caused by the fact that the API of custom-load-symbaol has no means to respect the setting of
> force-load-messages when loading a library.
>
> Please do note, that this analysis has been made by and is described in more detail in
>
> https://emacs.stackexchange.com/questions/82904/disable-echo-area-during-startup/82924#82924

I don't think force-load-messages is what you want, because that
variable is used for the opposite purpose: to avoid suppressing
"Loading FOO..." messages.  Whereas you want to suppress those
messages.

I don't understand why you want to suppress those messages, though.
Those messages are normal in Emacs: they are shown every time Emacs
loads a Lisp package.  custom-load is not special in any way in this
regard.

Why is it important to suppress that?