I use FullStory to study the behavior of users on certain customer sites and I noticed a trend in some customer sites where users would choose to use the links in the footer navigation on the menu main.
My initial reaction would be to affirm they do so because they feel that the interaction cost is lower than the main menu or because the footer navigation is simplified. simpler.
It may also be that after scrolling through the screen to the bottom of the page, the use of the bottom navigation seems less rubbing.
Unfortunately, I can not ask those users who exhibit this behavior, so I wanted to go here to see what other user experience professionals might have to say about it.