Because nobody wants to spend time crunching an Excel sheet when you can train a computer to do it for you, automatically, all the time.

Machine learn is also called statistical learning. It does not mean deep learning which is a subset of ML.

Creating a model in python or R is going to be much easier than in excel.

“Half of the time when companies say they need ‘AI’ what they really need is a SELECT clause with GROUP BY.” — https://twitter.com/matvelloso/status/1001899539484192768

If you have a strong ML work flow it’s going to be easier to scale and automate an ML solution than an excel solution.