Thanks for asking! First off--I'm not an expert! I'm merely a hobbyist. The following is only my opinion.
When it comes to the actual test--I totally agree! I don't refer people to an online test when they are questioning their personality type. Online tests are highly inaccurate and rely on a person knowing oneself objectively, which very few people can actually do. Some are better than others, but they are all inconsistent.
That said, the actual personality table I've found in my experience to be not only accurate, but useful. If you can figure out your type and begin researching it, provided it is the right type, it is almost guaranteed to be an affirming and educational experience. Perhaps because ENFPs tend to be very misunderstood, to have someone tell me that my personality wasn't wrong and that others also thought the way I did, it really boosted my confidence and helped me grow comfortable with myself. Before I knew what an ENFP was, I thought there was something wrong with me, because I grew up in a family of Sensors who rarely understood my emotions and thought patterns. Perhaps to some people, having a label on them feels like a chain or stereotype, but that wasn't the case for me.
I think though that if you start to read different descriptions of the same type, you'll notice that they don't always line up on the specific details. That's because even within the same personality type there are so many different kinds of people. Just because two people have the same personality type doesn't mean they will be alike at all. The personalty description is only a guide.
Does this help, and does this address your questions? Please let me know if I should explain anything further.