Mobile Website Landing Pages are a must.. especially 2014 and on.
It comes down to meeting your audience where they are at.
If they are on Mobile.. you gotta make sure your websites can be viewed on them properly.
Mobile Website Landing Page Tutorial
Get more training on building high converting websites, even mobile optimized
If you are looking for a full write up the tool suite I personally use to make mobile website landing pages and other “stuff”.
Check out my full leadpages review here