A page linked directly from your website’s home page, is going to be considered more important. So it can get high rankings more easily than if it is “deep linked” meaning it takes several clicks to get to it.
Does that mean you should load up your home page with hundreds of links to pages on every conceivable search term you want to rank for?
No.
The general idea – and this is only an approximation – is your home page has only so much “link juice” to transmit.
Too many links on the page and Google devalues ALL of them.
This is not something you can attach firm numbers to, like “no more than 23.5 links.”
It’s a guideline for what you can do to improve rankings, or what may be worsening them.