I'm Ujjwal Sukheja, Growth at Talkie.
Yes, you read correctly that talkie replaces slack from your workplace. We built this platform to help remote team so they can communicate efficiently with their co-workers without switching their windows or tabs.
but I believe you should not do this negative advertisement, "replace slack from your workspace" specially where in your app video you are using slack to get that PNG image :p.
I see your app as facilitator for small talks, which is actually problem and you are targeting.
small messages like - Are you there available ? - Are you joinig today's huddle - or so on
talks/messages which are temporary and not required any documented evidence :p.