Sumproduct Vs Countif

I have a worksheet where I am trying to count the number of occurences of several text strings.

For example:

I'm trying to count how many times "paid in full" and "fully paid" occur in column A.

I have two formulas, and both seem to work, but since I don't really understand either of them, I'm wondering which I should use and how I would adapt it to include additional text strings. (Like adding "paid" to the list)

Here are my formuals (I didn't write either of them, another co-worker did)

=(COUNTIF(A:A,"paid in full"))+(COUNTIF(A:A,"fully paid"))

=SUMPRODUCT(--(A1:A50={"paid in full","fully paid"}))

Also, if there is another and easier way to do what I'm trying to do, I'd love to know.