Using Testpoints as Pins?

I understand test is in the name but can test points qualify as regular pins in respect to accuracy and deterioration?

It depends on the product.

On some products test points are pins already but broken out in a different spot. Other products have test points that are not pins at all, just a place to verify a voltage is present. And other products have test points that might not be pins that are useful except for the initial programming of firmware to the device and have no use to an end user.

You would need to look at the schematic to be sure what your test points connect too.