Firefox and Safari would probably work for the majority of features but Chrome probably exposes some browser APIs that the rest don't that might make a couple things not work.
For people who know enough to spoof a Chrome user agent, they know enough not to mind if some things break but regular consumers wouldn't know about browser compatibility topics and would blame any irregularities not on their browser but on Snapchat, which is why they choose to display this error rather than let people through.
For people who know enough to spoof a Chrome user agent, they know enough not to mind if some things break but regular consumers wouldn't know about browser compatibility topics and would blame any irregularities not on their browser but on Snapchat, which is why they choose to display this error rather than let people through.