With Toolset Layouts you can, without using any integration code or Plugin, edit the_content() part of the DIVI (or any other) theme.
With DIVI especifically you can do that, and you can use Parent/Child Layouts, something that you cannot do, when you use any other theme that is not integrated.
You can not edit sidebars, headers, footers, or whatever that is NOT part of the_content().
If you want to do that, you need a programmatical integration.
Let me resume:
1. Any theme, not listed on our "Integrated Themes" list:
- you can edit the_content() part with Layouts Content Editor or a Layout created under Toolset > Layouts (and assign to a post/page or all of them).
In any case, Layouts will replace/edit the_content() part.
You can not Use Parent/Child Layouts.
I already filed all issues that actually happen, such as that you are able to insert Child Cells, but they will not work.
Once again, ANY theme that is not integrated in any way, you can edit the_content() with the Layouts drag and drop feature.
You can not use Parent/Child Layouts but only directly assigned Layouts or the Content layout Editor in the single Post Edit Screen.
2. Any Theme listed as integrated (and by now, this is only DIVI) without any Integration Plugin:
You can do everything you can do as in #1, but you can also use Parent/Child Layouts.
Everything still only applies to the_content().
Nothing else can be edited with Layouts.
Header, footer, sidebars and so on still are determined by the theme.
3. Full integration, which means, you can edit Header, Footer, Sidebar, and whatnot, requires elaborated Custom Code integration for which I can give an example Theme:
hidden link
Please read the inline Comments there carefully, I spent a lot more time commenting my code than actually coding it 🙂
It is a very SIMPLE, MINIMAL Theme that FULLY integrates Layouts and even lets you choose DYNAMICALLY if you want to use it or not (even if enabled on site).
This are the 3 situations you can have.
There is a 4th situation, and that is when the Theme does not use the_cotent() but a Custom Function, and/or customozes Bootstrap classes.
Such a case is EXTRA.
TO answer your questions:
Layouts, used with DIVI and no Integration, will basically do the same as a Content Template does, but of course Layouts has a bit more power, such as Drag And Drop, Accordions, Tabs, and what not.
Those things, are not present natively in Content Templates.
I hope, things are clear now.
I made extensive tests yesterday, on which I base my above information.
I know, there are sever issues with messages, how we name things, and even some bugs such as wrong links and worngly present cells that are not to use in some cases (as elaborated above).
All those issues have been reported by now.
I also know (and reported) that the current Layout Plugin is pretty confusing, specially when you try to understand the difference of Template and Content Layouts.
Also this is reported and I suggested several edits and adjustements.
I was Toolset Client (User) in past, and I am still an User, means, I still do develop Websites with Toolset as a "End User".
So, I can afford to say, I can look at it from your point of View.
I see what you see, I don't only see what a Developer sees.
With this I want to say, I suggested things to be changed, that will only be obvious to an USER and not to a Developer, becuase a Developer usually, well, develops the code but does not really "use" the Plugin (even thou, of course, it is tested and all that).
But onla an End User is a proper "usabiltiy tester".
And that is what I spent my day yesterday with.
So, I hope I could explain everything clearly now, and I reported several(!) issues.
Anything, I am around until tomorrow, then 2 days weekend (see my profile: https://toolset.com/forums/users/beda-s/)
So, feel free to ask/feedback anytime.
Thank you for your kind patience.