Thanks for raising this concern. To make it clearer, we do collect the data to do processing but then we delete the conversations and the executive summaries we generate after sending them to our users.
I am no security eggspert but I think if you encrypt them while they are waiting on disk to be processed then decrypt them in memory only to process them anD then delete from memory and delete from disk, you will have a better claim to privacy. Also, must transport over SSL.
You might not _store_ the data, but you absolutely do "collect" it.
(Nitpicky would be "well... you do store it at least a little while; even if only in RAM".)