This doesn't make sense generically since not every software has all the features of other software.

But to be more specific - pick their concern, describe the replacement workflow with Sheets, then explain how it's a good replacement

> The only question is wether they want to learn doing things differently.

Of course it's not the only question, among many other questions could be whether they can afford to spend a lot of time/money after learning (though this investment also shouldn't be ignored) to do the same thing, and whether they can do the same for all the people depending on the current workflow