I will still keep on using the datepicker because it does exactly what I need it to do. It picks the date for me.
I see that you're very persistent to say the least 
, which is good for the community.
The work you've done is impressive, considering that is free. I had a look at the updated space lua / javascript implemenation of your datepicker. Big wall of code to get lost into . Previous one is a bit smaller.
Until @zef or whoever in the community ( even me if I find the time and energy), comes up with a proper collapsable (persistent) block, I would rather stay with the medium wall of text in my CONFIG.md file. It has already become unmanagable to go a read and find something.
I currently have headers which I have to collapse one at a time until I reach the spot I need. And yes I already know about your TOC on the side :), but for the same reasons I have avoided it so far.
Although the discussion is shifting away from the main topic post.
So for anyone else to follow along. The updated DatePicker add-on as SlashCommand - #19 by Mr.Red, now includes the formatting and date referencing configurable. You don't need neccessarily a custom getPrettyDate() unless you want to also override the /yesterday and /tomorrow slash commands. I'm pretty sure that @Mr.Red will make another update soon to include them also 
.