How is it based on anything in Excel? There's nothing about test plans in RF. Test plans are about schedules, strategy, deliverables, roles etc. And those are typically garbage. Absolutely nothing related to RF.
Might be difference in local terminology, but by "test plans" I mean spreadsheets, typically in Excel (sometimes printed and bound), that described step by step every test for manual tester to follow.
And that's how a lot of testing is done in various companies, especially where manual testing is still common, at least in Poland.
I've never seen a manual tester follow the steps that are written down, but I've seen a lot of effort put into writing down the exact steps anyway.