In case of Bitcoin pubkeys you don't want to publish them anywhere for privacy reasons (that turn into real physical security reasons once you have enough BTC). Also, notice how pubkeys are normally hidden under hashes and revealed only at spending time. This drastically limits attacks on ECC if/when some weakness in curve math is discovered. And if quantum computer is invented tomorrow, people can safely transition funds to a new signature scheme by introducing 2-phase commitments to safely reveal (now crackable) ECDSA pubkey after another transaction was made with commitment to concrete signature (preventing double-spend attempts using a cracked key).