I’m actually in the process of implementing this periodically for our real estate agency. We have three divisions of the business and so it’s a little tricky, but especially in real estate where we are trying to gather leads and contact it’s a very popular way to work around the linktree stuff that doesn’t seem to get much traction at all. 

We have tried it once for a challenge, using Manychat (we also have a chatbot in our DMs via this tool). We said “comment xyz for the terms and condiotions" so not many people did that, but it did work. I am curious to test it more.
We would also love to try it for common customer issues, such as “where is my order”. However, we would need to very clearly define the keywords, since you don't want to randomly DM a customer about an issue they aren't experiencing 
Here's more info on Manychat's functionality. Let me know if you try it!

Insta has put out statements that they’re going to deprioritize these types of posts in the algorithm, so long-term, I’m not sure if it’s the best approach. But right now, I still see influencers and brands taking off doing this. And yes, people use Manychat for it. It’s a freemium model at first.