I doubt it has any SEO effect, but it might be useful for the people that visit your site(s). For that reason alone I wouldn't discourage the practice. There are, after all, a huge audience of actual people who visit web sites as opposed to just search engines stopping by.
Here's an example of someone loading the footer with related site links although ...
It won't be toxic for your websites but it won't do any good as well. Google gives value to backlink in decreasing order of their location on the webpage. So a link on the first paragraph is worth a lot more than one at the last. Source.
And the links on the footer get the least value.
On the contrary, it might feel spammy(just my opinion) to google if ...
I don't think it would be a good idea to get backlinks from footer section. It's not a good practice in SEO. Backlinks are more strong when they are connected through your content not just sticking in footer with one anchor link and generating lots of backlinks.
I don't think it would be helpful.