This means that if you’re hoping to do voice chat with your friends while playing Minecraft, you can pretty much scratch that off your list. Instead you’ll probably have to setup some other system and use third-party apps like Skype, Discord, Teamspeak, and so on which is probably not that convenient.
This is versus the Wii U version of Minecraft which had in-game audio, so it does seem a bit odd that Nintendo/Microsoft isn’t including this feature for the Switch version. As Cube3 notes, this probably means that we’ll have to wait for the upcoming release of the Nintendo Switch app for smartphones before we will get in-game audio chat capabilities. Hopefully that won’t be too far behind as games such as Mario Kart 8 Deluxe are also lacking the feature.
It shouldn’t really detract from the overall experience, but players who prefer communicating over voice will be missing out on this feature for now.