I think everyone at this point knows Slack. It is a messaging app for businesses. Recently sold for $28 billion to Salesforce.
So why is it so successful? Well I had seen someone suggest it was word-of-mouth, or that they listened to their customers and not some big marketing budget... Although I did see on Yahoo Finance they quoted SEC filing that showed Slack spent 50% of its revenue on Sales & Marketing. So we are talking millions.
Now why does this matter to you. There are a number of benefits but the main two are:
This is why it is important to integrate with services that make your product stronger and not waste time trying to compete.