With Ottspott you can set to receive notifications in Slack and you can use the Ottspott bot for multiple actions. The Ottspott bot can only listen on the public channel not in private channel.
So please don't move your channel(s) you used with Ottspott in "private" mode. A private Slack channel cannot be set again in public mode, so you would have to uninstall Ottspott from Slack and start the whole onboarding process again.
If you would like to keep some information (transcription or recording files) private or limited to some members of your team, you can pick another number with another channel and just invite the right members on this channel.