Off topic, but when you write something like this the message you’re sending is “I’d rather insult the reader than take the time to communicate in a way that can be properly understood.” Hopefully that’s not the intention.
There is no other way to communicate nuance that I've found. If you claim that "some types of X are Y", you'll get angry replies about how some X aren't Y, angry replies about how terrible it is to claim that all X are Y, and on more than one occasion, angry replies about how some types of X are Y.
If you're insulted, well, then, it's not targeted at you. But abundant experience says it does have non-zero targets. And it's getting worse, not better, as more and more people are convinced(/programmed) to believe that reading people as harshly as possible and then being as angry and offended as possible is a virtue rather than a vice. As these people get more power, it's becoming simply self-defense to make sure you underline your point.
The depth of those integrations serve as the depth of the moat. If your integration is basically "I send and receive textual messages", which from what I see the vast majority are, you've got an integration which could be ported to a competitor in less than a week. A lot of the integration work is in the thing being integrated rather than chat-system specific things.
As you use more Slack-specific features the moat gets deeper, but you do have to stretch a bit before you're really "slack-specific". Rich text formatting, conference rooms at a basic level, etc. isn't "slack-specific".
(Be sure to read that first sentence of mine a couple of times before replying. It does not say "integrations are always trivial to port and are thus irrelevant", for instance. If I wanted to say that, I would have.)
"Atlassian throwing in the towel on HipChat and Stride."
I strongly suspect that Atlassian threw in the towel not because it was hopeless, but because a highly profitable company has a business imperative to avoid things that will merely be sorta profitable to them, or where profit will be harder than their other highly profitable activities. It's why Google doesn't simply do everything; put over-simply, for something to be worth Google doing, it has to be more profitable than putting another engineer on AdWords. When a company is valued at $7.1B, it validates the market, and even if there was no competition today, there most assuredly will be in two years!
(I work for a company not quite as high as Google in the "necessary profit per engineer" metric, but we've also divested "merely" profitable businesses because they were basically a drag on the rest of the company, and lacked sufficient strategic value to overcome that disadvantage.)