Is it a good idea to have a ANA test nowadays?

No. Having a laboratory test, any test, in isolation is generally not a good idea. By design, about 5% of the test results are false positives. Laboratory tests should be done only if clinically indicated, with the exception of a few validated screening tests.
If symptoms. The ANA is very helpful to screen for lupus and other autoimmune diseases but is not helpful for people without concerning symptoms. Ask your doctor if you should be tested. The gold standard type of test is called immunofluorescence (not elisa or "direct").
For What? The ANA test is a test performed for certain clincial indications including the presence of lupus, other connective tissue diseases, clarify the cause of clinical symptoms to see what the most appropriate diagnosis is. It is performed to help the diagnosis. It is not done unless indicated. Doing that would not be cost efficient. The test is done to look for and confirm a diagnosis.