I'll take csv over xlsx any time.

I work a lot with time series data, and excel does not support datetimes with timezones, so I have to figure out the timezone every time to align with other sources of data.

Reading and writing them is much slower than csv, which is annoying when datasets get larger.

And most importantly, xlsx are way more often fucked up in some way than any other format. Usually, because somebody manually did something to them and sometimes because the library used to write them had some hiccup.

So I guess a hot take indeed.