There can be many different reasons to consider a shifting to Biblatex editing mode in Jabref, but my reason was pretty straightforward. After several minutes of trying to find a way how to cite links and online resources in jabref, I discovered that the option simply wasn’t visible in jabref because it was functioning in bibtex mode.

 
When you try to access the BiBtex menu by type, none of the options available are suitable for online references:

How to cite online resources in jabref

As per this article, while using the bibtex mode, the way to cite online references is by using the @misc, but to me the @online seems like a more appropriate way to cite online resources, which is a feature that comes only in the biblatex package, so you have to be editing your bibtex document using the biblatex mode. There are numerous other advantages that come with the biblatex mode as well, so it makes sense to use it.

How to switch to BibLaTeX mode in latex from BibTeX mode:

To control which one is selected by default, go to preferences>General> Default bibliography mode> and pick your choice.
When a document is already open and you want to switch from BibLaTeX to BibTeX or vice-versa, click on File> Switch to BibLaTeX or BibTeX, as applies to your situation.

Change the mode to BibLaTeX, for an ability to add online citations. Once you do that, and try to create a new entry, you are greeted with this screen:

You can now select “online” or “WWW” as per your preference.
Disclaimer: I’m not a LaTeX expert