I've built my first E-Commerce (website) Store! This was for my sister's Arts & Crafts business, which took me less than a week in total to build.
Overall, I'd say I'm very satisfied with how smooth the process was in building a store through Squarespace builder. It may be “limiting” in the customization side of things, but it is well worth the shot once you're able to get a rhythm with the tools.
It's simple, yet effective with no hassles in publishing your website around the globe in just seconds...