Big big reason: R doesn't alter data without being asked to, Excel does so, silently, sneakily. Anything important should not be done in Excel. https://www.theverge.com/2020/8/6/21355674/human-genes-renam... https://stackoverflow.com/questions/165042/stop-excel-from-a...
I've used perl, python, and R for scientific data for a really long time but have always made a concerted effort to avoid Excel. My reasoning feels the same as when people say Java is the best language because it can be run on any device, which is like saying anal sex is the best sex because you can do it with any animal.
Maybe I'm missing out on a great experience, but the notion has always made me uncomfortable.