Advanced website builders — the tools provided by Squarespace, Wix, Weebly, The Grid and more — produce websites that look and feel like they were designed and coded by humans. They’re also software as a service, which is a different business model than traditional, custom-developed websites.
So, should companies use them? At some point, will they replace custom development? In short, yes.
Source: Smashing Magazine The State Of Advanced Website Builders