Latency on wireless controllers isn’t a big deal (and a lot of Smash players are using wired Gamecube controllers anyway), but it’s not a big deal on wi-fi either. The problem with wi-fi is packet loss and not being able to send and receive at the same time, which feels like latency in fits and starts, because it has to wait until the packet sends successfully. Ethernet helps with Smash, but it still sorely needs rollback netcode regardless. Even on a wire, you’re still on delay-based netcode.
they do use bluetooth. However, it should be noted that not all BT devices are created equally. Check out this table from RTINGS.com of reviews of wireless bluetooth headsets. You can see that the very worst headsets have 300+ milliseconds of latency, while the very best have almost 0 ms of latency. I imagine that the Joycons hit a similarly low latency.
Latency on wireless controllers isn’t a big deal (and a lot of Smash players are using wired Gamecube controllers anyway), but it’s not a big deal on wi-fi either. The problem with wi-fi is packet loss and not being able to send and receive at the same time, which feels like latency in fits and starts, because it has to wait until the packet sends successfully. Ethernet helps with Smash, but it still sorely needs rollback netcode regardless. Even on a wire, you’re still on delay-based netcode.
Don’t the Joycons use Bluetooth, which are pretty laggy on their own? I know I absolutely do not like using BT mice.
they do use bluetooth. However, it should be noted that not all BT devices are created equally. Check out this table from RTINGS.com of reviews of wireless bluetooth headsets. You can see that the very worst headsets have 300+ milliseconds of latency, while the very best have almost 0 ms of latency. I imagine that the Joycons hit a similarly low latency.