The problem is that it's just that - the feeling of being seen and understood - the whole point is that there is no actual interaction with you. Depending on your life situation, you can keep up the delusion for quite a while and be happy with it (like the guy who happened an anime character) - things get problematic once you require some actual understanding and life advice.

Even in interactive context, things are treacherous. Sure, you can have this online community who totally get you, who you can talk to about anything and get back compassion, support and useful advice - but do you have any idea who those people actually are, what their life situations are, what values they have and what views they are basing that advice on?