It works until you need Excel. I have yet to find a business which doesn't use Excel in some capacity. As in proper Excel, not somewhat dubious compatibility Excel (LibreOffice).
I'd still argue large swathes of things we take for granted on other platforms don't exist or don't work either.
To be honest, probably. The vast majority of users don't need the advanced features of excel. I've seen people be awed by pivot tables. I'm sure some people need those extra features, but I'm guessing vloopup is about as fancy as it gets.
We do it for all of our quarterly planning so that's a sync with Jira as a datasource, multiple tables and pivot tables, etc. I'd say the whole thing is probably a few MB.
I don't know where you'd start to see a performance difference compared to Excel for Win32.
I'd still argue large swathes of things we take for granted on other platforms don't exist or don't work either.