This isn't just about Dropbox. Notice the enhanced collaboration with Slack and Atlassian (which is already an equity holder in Slack).
This alliance looks like an attempt to displace Microsoft in owning the "office runtime". You have Microsoft's Teams, Office 365, and Github vs. Slack, Dropbox, and Jira.
The interesting thing is that Google is actually in a much better position to do this by way of GSuite, but their own internal messaging answer to Slack hasn't gotten out of pre-launch.
This alliance looks like an attempt to displace Microsoft in owning the "office runtime". You have Microsoft's Teams, Office 365, and Github vs. Slack, Dropbox, and Jira.
The interesting thing is that Google is actually in a much better position to do this by way of GSuite, but their own internal messaging answer to Slack hasn't gotten out of pre-launch.