I am guessing two possibilities:
1. The friction to onboard new users would be pretty high as it currently stands, if they have to go and figure out using a key extension.
2. The developer, in this case @hodlbod, would need to trust that the signing extension options are excellent, and have been audited rigorously.
I can imagine that as a developer, if one knows one is acting in good faith, it might be easier to trust oneself and one’s  intentions, than those of others?

Curious to hear thoughts, esp from developers nostr:npub1jlrs53pkdfjnts29kveljul2sm0actt6n8dxrrzqcersttvcuv3qdjynqn  nostr:npub1xtscya34g58tk0z605fvr788k263gsu6cy9x0mhnm87echrgufzsevkk5s  nostr:npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z  nostr:npub16c0nh3dnadzqpm76uctf5hqhe2lny344zsmpm6feee9p5rdxaa9q586nvr   nostr:npub1g53mukxnjkcmr94fhryzkqutdz2ukq4ks0gvy5af25rgmwsl4ngq43drvk nostr:npub1v0lxxxxutpvrelsksy8cdhgfux9l6a42hsj2qzquu2zk7vc9qnkszrqj49 nostr:npub1xdtducdnjerex88gkg2qk2atsdlqsyxqaag4h05jmcpyspqt30wscmntxy