I think Excel is still important in so many ways. Over 50% of my users want to be able to easily export their data to Excel. And they want it in a way that they can work with the data.
If you are not living in America or the UK you know the issue: It is hardly ever possible to work with exported numeric data. Formatted European numeric data get mutilated by Excel in a terrible way. I used the features that Data Tables provides to get it done - somehow.
But then the next problem emerged: How to do it,
a) if the user wants only selected columns (selected with the colvis button), or
b) the user wants wysiwyg: only what is displayed on the screen (not including child-rows hidden by the "responsive" extension)
- and still get the export formatting done in order to prevent Excel from destroying part of the data.
This was hard to develop and my code for this is ugly, I think.
I would strongly encourage a better solution for this. If anyone is interested how I resolved this with my ugly solution I can share it.