No, it's not fiction. Erel suggests (and encourages) the use of B4JPackager11 because the resulting exe (for Windows) contains a copy of the Java runtime right for your app, (i.e the same version used to test and compile) so the machine running your code won't need to have an already installed copy of JRE (which could be a "wrong" version btw).
Same for older B4JPackager for version 8.
On the other hand, when you install JRE 8.251 on a PC (provided you compiled the app using that same Java version), you can just deploy your *.jar file on that PC and run it (double-clicking if the OS can find java.exe).
As an example, I have JDK 1.8.0. 201 on my dev machine and in Tools/Paths configuration the first box (javac.exe) points to it (C:\Program Files\Java\jdk1.8.0_201\bin\javac.exe). A *.jar compiled with that config could go (and I do it) to a Windows/Linux (Mac not tried) where JRE 1.8.0.201 is installed and ran w/o problems.
Once I'll upgrade to JDK11 I'll go the B4XPackager11 way to deploy even if I don't like the waste of space due to multiple copies of JREs