This is troublesome regarding for an example images. Images are hosted on static.parastorage.com and the same goes for a lot of other resources.
By using external domain instead of the premium domain we have we can't access features like image looseness and optimization on services like Cloudflare.
Let's say when I get my premium package you could create images.wixshow.com that actually is just a pointer to the static.parastorage.com. Then I could create caching and optimization rules for those resources and make full use of Cloudflare as a speeding tool.
Please consider serving all site resources in subdomains under the premium package domain for full use of external tools and increasing the score of the site as well.