The problem these tools solve are more related to infrastructure rather than one's ability to code. Learning to code might be the easiest part but deploying it, maintaining it, scaling it, securing it and integrating it with thousands of other services remains a huge task even for experienced folks. It's wasted time and effort for something that is cookie cutter in functionality and limited in scope (vast majority of web).
Some of them provide collaboration tools, development environment and experts on call which is neat.
Add ease of outsourcing, too. The employer doesn't have to worry about maintenance once the product is finished. Many good platforms will allow you an easy migration path and better security controls. That comes at a vendor lock in. That's the price but given the life expectancy of smaller companies and startups, it may as well be worth it.