Yes it’s a bit confusing but there are many posts that explain the difference.
Basically, the free account plan just allows you to create 2 unhosted projects - i.e. so you can only build up to 2 sites using xxx.webflow.io (staging)
Without a hosting plan - up to a max of 2 pages per site (there is a way around this by cloning a site with more than 2 pages)
With a hosting plan - a lot more
Hosting plans - means you can put a site Live. This depends on your needs - i.e. a basic static site, a CMS site, or an ecommerce site.
There is a restriction (infact quite a few) -
If you want to publish the site - you need to upgrade your hosting plan
If you want to use more item fields in a CMS - you’ll need to upgrade your hosting plan
If you want to add any custom HTML code - you’ll need to upgrade your hosting plan
However in conclusion - depending on your branding site - it may be easier to just build it first on staging, then add a hosting plan as you see fit, i.e. basic first, then CMS.
You should not require any upgrade of your free ‘Account Plan’
Hope that helps.