When would you use "more than" then?

[yo4561]

Happy Thursday!

In the All the Verbal Book, MP has the following:
For comparisons using the word “numbers”, use “greater than” not “more than”
Example: Its numbers are now suspected to be much greater than before.

Is "greater than" only for numbers then? What is the main difference in use between "greater than" and "more than"?

E.g., this is wrong to my ear, but I wanted to confirm: "I like Sally greater than I like Henry."

Many thanks in advance

[esledge]

Is "greater than" only for numbers then? What is the main difference in use between "greater than" and "more than"?

No, "greater than" is not just for numbers. For example:

Artist A is greater than artist B. (Here, you are comparing greatness!)
My love for my dog is greater than even my love for pizza. (Neither pizza nor my dog are numbers.)

E.g., this is wrong to my ear, but I wanted to confirm: "I like Sally greater than I like Henry."

This is wrong, but it's not because "greater than" can only go with numbers. Be careful: you are turning the rule around. If comparing something with the word "numbers," use greater than, but that doesn't mean that if you use greater than, the compared things can be, must be, or can't be numbers...it just depends.