Pretty much all Shopify shops have their own domains, only a minority drive traffic to their .myshopify.com subdomain
Seems someone would first effect to have a better branded site. As in, a decent TLD.
And that if anything, this is a kick in the pants of an ecommerce site to get its own domain(s) to deal with this.
Do I have that right?
Of course, that specific example, since Google is trademarked and well known might get you on the wrong end of Shopify's ToS or a UDRP request either way.
FWIW, it looks like a 301 to a new domain should transfer the seo juice. If the site is valuable, a new domain should stand up pretty well. It also decamps from myshopify.
This all seems more valuable to the store owner, but I get why people would want to avoid all those changes and just try to figure out the thing "Apple is making them do."