You arrive at one.google.com and all it says is something about your storage. Is that what it's all about?
Here's what it says in the Google Description (you have to Google what one.google.com is to find out what it does - hilarious!).
"Get expanded cloud storage, access to help from Google experts, and more benefits — in one simple plan that you can share with your family."
So, from this it's storage + experts + some mysterious other benefits - and it's about sharing it with your family.
Why don't they at least say that on their front page?! The reason, cos Google don't employ any decent usability experts.