yes.  

consider the added complexity of having at least 60% of your audience using a 2.5x3.2'' phone screen instead of a proper monitor on a laptop.

eyeballs are not set phone size apart for reference.  theres a reason monitors are the size they are.  so the eyes can look straight forward without having to constantly shift focus to see the thing.
all this makes mobile navigation a giant pain in the *** and honestly, I never use my phone.  But every few weeks I'll load my site on my phone to see what it looks like, just because.