The problem with public key cryptography is that anyone can lock money, in any chain, to your nsec. It doesnt even matter which curve we use as Nostr. Anyone can always send you any token or coin from any chain. There is not going to be any future where that doesn't happen. And in many cases, the sender can actually proove that you are the only one in control of those funds, like it or not. Which means that you can't disallow people from sending you money in your key in the same way that you cannot block say Iran from dusting your UTXOs with tained coins that you are forbiden to have a relationship with.