Historically, all FreeBSD kernel modules needed to be loaded by loader() before the system booted, but that comes with a price, boot time is much slower if all modules are loaded this way, as it forces them to be loaded sequentially rather than in parallel. So, the more you "throw" on /boot/loader.conf the slower the boot process is. Keep only what is needed in boot/loader.conf and for the rest useI apologize for asking but I’m unable to make a direct comparison myself at this time.
kld_list
(/etc/rc.conf) which by the way can load them in parallel after the base system is already up.