I have been a web developer for over 6 years now. Back in the day it was all about Adobe Fireworks and Dreamweaver. Once you designed a website for a client you would forever be enslaved, maintaining that website for life. In 2017, platforms like Squarespace, Shopify, Wordpress, Wix and others have changed the game. For small clients I can create a website and teach them the basics of updating and editing it themselves.
Squarespace is definitely one of my favorites. The biggest reason is that it makes sense. It is by far the easiest for my clients to learn without limiting me to templates.
It's easy to add custom code and code blocks, the apps make it easy for my clients to update and add new content without having to login and everything is sooo intuitive.
If someone say, "I can't do this with squarespace" then they probably don't know how to use it very well. The only downside to Squarespace is that they do not have a POS system. When I get a client that needs a large online store, this is not the best solution. A better alternative would be Shopify.