Mostly memory management and 64-bit support finally being on-par with the 32-bit versions, but it's hard to argue the nuance overall.

I wouldn't trust an "Excel guy" who said that, they aren't staying current/using new functionality.

Just off the top of my head:

IFNA, FORMULATEXT, DAYS, CONCAT, IFS, SWITCH, XLOOKUP/XMATCH, FILTER, UNIQUE, LET, TEXTBEFORE/TEXTAFTER, LAMBDA, et al.

But my favorite improvement is the "don't intentionally corrupt CSVs" options found in Settings -> Data -> Automatic Data Conversion (hint: Disable everything). Only took them 30-years to add that. Absolutely absurd these are enabled by default still.

Excel is one of Microsoft's best pieces of software and one of the very few they haven't turned into slop YET. Still don't understand why we don't have local-only Python to replace VBA at all license levels (i.e. non-cloud).

XLOOKUP was introduced in 2019. I thought it was a great update

I'm an Excel guy and 2013 was an improvement over 2010 with very little to dislike.

Those guys aren’t using Excel very much.

You can take LET and LAMBDA from my cold dead hands