Basically it means that more ETH has been destroyed forever than it has been mined.
I don't think that this is anything exciting, it's just for more of an attention grabbing headline than anything else.
People are quick to jump to conclusions and hype up anything and everything imho. This is certainly a one-off event that is going to not be a very impactful event going into the future i think.
Isnt it exciting enough since in that day, instead of increasing the number of coins by producing its, we decreased because we had burn so much coin.
Im just excited because I dont think it will happen frequently.