Email sometimes takes too much to be received by the user, but the approach could be handy in other contexts. For example, some time ago made a Slack bot with

Email sometimes takes too much to be received by the user, but the approach could be handy in other contexts. For example, some time ago made a Slack bot with a web dashboard. The authentication method was based on introducing your Slack username and the bot would send you an OTP. The latency problem didn’t exist here.