Opinions differ. My opinion is that markdown is pretty bad and I don't think it will be the future.
Example of this is that none of the users did not know how to use markdown, but did not have much problem with BBCode (learns pretty fast). If markdown shorter, does not necessarily mean that one is better.
Users simply knows that B is bold, URL is link, IMG is image and just put it between tags and it's harder to mix with raw text than markdown. Also, I remember on old forums (and also new) you have option to create your own bbcodes and insert HTML for tooltips, embed youtube video or any other video, spoilers, text highlight and any other HTML code.
There are many more options and the more flexible. Markdown is designed for simple formatting (bold, headings, lists and a few other small things).
One of the users asked me how to insert clicktable image with Markdown. I show him and he answered me: "Wow, it's scary! How, invented this?" And I totally agree with him.
After all, it does not much matter. I do not see a future in Markdown. Also I think it would be much easier to use BBCode with WYSIWYG editor than Markdown because BBCode structure is logical like HTML structure.
However, I decided to use another forum, because NodeBB is very buggy (see first posts).
Of course, this does not mean that I will not follow its development, but as long as there is a great incompatibility with plugins (after core update or similar) and no integration of user sessions and database, I think that this forum will be limited to a smaller number of users.