I saw it on this video: nostr:nevent1qqsdz7asszea9ss58m0ensrkjfmwpcu8mnfcf52eeyl3gtsca0e0v8gpr3mhxue69uhkummnw3ezucnfw33k76twv4ezuum0vd5kzmqzyrh7tw7gx3vqd680fu0hew8slsqpf29hgd4q5p7lmt5akf5hwkldjqcyqqqqqqg0sqs39 

 I say it's secure enough. Though if you are going to be using DMs, know that people know who and when; but not what.