Thinking about it, there are two major differentiators between Snap and those two. First is the order in which you choose who to send a message to and what the message is. Second is how you can send the same message to multiple people simultaneously.
With Messenger & Insta you choose your recipients first, while with Snap you take the picture/video first. This is naturally easier for a spur of the moment message; you don't have to think about who you might want to send it to while the thought is still fresh, or indeed while whatever it is you're snapping is still happening.
Snap also has a great model for sending things to multiple people. Say I'm taking a picture my cat doing something silly. It's not interesting enough to go on my story (by whatever metrics I have for that), but I also want to send it to multiple people. There's no way I'm going to create a group just for this; it'll never be used again and there's no reason for the people I choose to be connected with each other. Snap solves this in a way that Messenger and Insta don't (or at least if they do I've not seen it advertised). That's not to say groups aren't really useful -- I'm surprised it took them so long (years?) to implement them.
I will say that their Android app is more or less garbage and should be an embarrassment to the company. It doesn't function right, it's slow and clunky, and it's infuriating to use and I've moved to IG more and more as its gotten worse. I know Snap is addressing that issue by rebuilding the app, but they have only started caring recently.
Aside from that, the disappearing nature of chats at all (be it text, image, video) I believe also leads to more engaging conversations. Participants have to be paying attention to one another lest they forget the last response, in stark contract to every other popular messaging platform. The result is that less conversations happen, but when they do they feel more engaging (and addictive... no doubt this is part of the strategy).
If you couldn't tell, I'm big on snapchat as a messaging platform, not as a social platform.
As a user, I think this is why most people fail to understand it or use it. Even if one has friends on Snapchat, if you go in trying to use it as social media you're going to be confused. It's a personal messaging app that happens to have some small social aspects, a map that I occasionally use so I can see where people are, and publisher content when I'm looking to kill a few minutes here and there. But 90% of my time is spent messaging people with pictures / chats, and groups are amazing.
> Investors who reviewed the data also said the fact that people are sending and receiving so many photo messages on the platform gives it a huge leg up on iMessage or Facebook Messenger.
> The majority of conversation that happens on most chat apps is text-based, and other platforms struggle to get users to exchange photos or videos. Investors said that completely visual messaging at this scale is “a pretty big deal.”
> All of this backs up Spiegel’s own depiction of Snapchat. In the past, he has said that users taking selfies on the app aren’t being vain or snapping photos to post later on social media, they’re “talking with pictures.”
I get the appeal of Snapchat but never got into using it. The only social media chatting I use is Facebook and I do it with other old people who prefer text. Is there something about the Snapchat implementation that makes image-chatting more natural and frictionless compared to Facebook or Instagram? And what leverage does this image-heavy chat habit have for Snapchat, if those users can't be drawn to the other money-making features?