Useful for getting a ballpark figure on your credit score. But it's not what a lender will use, and so the score the lender sees will be different.

Also, there is more to getting a loan or a credit card approval than just your score. Credit scores don't look at your income. They aren't based around how much you make or how consistently you make it or anything similar. But a lender will care.

In the case of a home loan, the credit scores are also not looking at your down-payment, but a lender will.