It’s not illegal to use encryption if your transmission is below 1 watt, such as normal Wi-Fi. If you want to use more power, then you need to get a license and your traffic can’t be encrypted. Licensed amateurs can use orders of magnitude more power and cover areas city wide, rather than barely within the confines of a home.
Slight correction, Lora is shared with amateur bands, but the transmission power is low enough that it’s within unlicensed limits.
Also, they can actually transmit quite far, they just can’t penetrate well. A mountaintop node can communicate to the horizon, but inside a house at desk height it can struggle to reach a half mile.