Just to add to this, it really depends on what you are wanting to do in the end of the day.
If you want a blog platform then there are blog platforms like WordPress, in fact I have been using DMXZone extensions for many years and more recently Wappler as my development tool of choice, yet if a client had to ask me to add a blog to their already developed Wappler website I would still install WordPress in a blog directory and use that for the Blog. If a client wanted a highly complex shopping platform I might still look at Magento or OpenCart possibly.
WordPress, Magento, OpenCart are just quicker and easier for those particular jobs i need performed, i do not even like WordPress personally, but it would take weeks to create something as powerful in Wappler.
If my client came to me and said they wanted a website for their hotel on the other hand I would not even hesitate and open Wappler right away to get started. The hotel website would have a combination of static as well as dynamic content and would mainly be visual with small server interactions such as for the enquiry form, maybe a mapping area, a newsletter subscription form. So Wappler is far more powerful than what is needed in all honesty.
In a years time however if they asked me to then add geolocation to the website, or ask to have internal staff make minor textual alterations to their website, or link it to their MailChimp API, or make it send users a birthday greeting on their birthday, or any other imaginable idea, it can still all be done in Wappler.
The next year they ask for some management interface for their website in the form of a backend dashboard, well i can just open Wappler and continue.
If they want it linked to a booking engine it can also be done, and if they wanted a custom fully built booking engine it can be done, and if they wanted me to then integrate all this into their Accounting System, it can also be done.
The point I am trying to make is that with many other tools, they offer the design tools, but when you have a need to add to it, you are stuck rebuilding the site half the time instead of just extending to it. Unless you are a manual coder you will not really find this level of flexibility in any other tool i have tried. I in fact am a manual coder and really use Wappler not because I do not know how to do it manually but because what takes me 3 hours manually coding, i can do in Wappler in 5 minutes most often.
For additional training resources there are some user built training materials such as wapplerunwrapped.io or my own one which is still to be completed at learnwappler.com
Maybe one of these might help a little. You are correct the documentation is lacking, unfortunately this is due to a very rapid development cycle as well as that the tools in Wappler are so robust that i might use a particular component on one project to do something simple like give the user a list of facts about Disney characters, and then the next day use the exact same tool to build the semantics for the next Russian space probe. Silly example but you get the idea. Every tool has 1000 use cases and to document what each user might want from the tool is very difficult.
My daughter of 19 is learning Wappler currently after a 3 year fight with me, because she said WIX was easier, then suddenly she side-graded to Pinegrow, then she decided WordPress was the answer to all her troubles, basically she ran into trouble with each tool at some stage of her website building hobby, WIX could not do X, so she switched to Y, until that could not do something and she would switch to Z. In 3 months on Wappler she is kicking herself that she had not made the move sooner, ok she does have me to ask every damn 10 seconds but thats besides the point 
EDIT from my Daughter who read this on her computer: If I had done what dad told me to do 3 years ago I would have had to learn manual code, and I would have grey hair and ugly nails, Wappler is not manual code, therefore 3 years ago dad was still wrong.