If they do serious financial work I for sure hope they do not use Excel or any other spread sheet tool. It can go wrong so many ways.

I know a few people who use Quantrix for financial modelling. It is an exceptionally nice piece of software, basically the successor of Lotus Improv, with Improv's more robust and auditable separation of data and formulas.

Do you know anyone who does serious financial work in Excel?

I know plenty of people who think they do. I know a few that cost the world economy about a trillion dollars: https://inthesetimes.com/article/the-excel-spreadsheet-error...

I used Apple Numbers for all my spreadsheeting so it depends what you mean by "serious financial work". The vast majority of folk could probably get by without using Excel I am guessing.