I’m sure you’ve heard the news by now: Teams and Skype for Business will converge into one. Here’s the official blog post: https://blogs.office.com/en-us/2017/09/25/a-new-vision-for-intelligent-communications-in-office-365/
And other articles for reference:
SuphatraConnor Slack commented
I prefer having them separate. I find the Teams UI and functionality to be much better & easier to use than the interface for skype & our users feel similarly. We've actively avoided using skype for team chat thus far because it's so messy.
How I break this down is:
If you want a more video-conferencing centric chat application, use skype
If you want an O365 integrated and managed alternative to Slack or Hipchat, use Teams.
Please do not merge the two.