There's a physical layer of the screen between the touch glass and the LCD that can be turned on, reducing the viewing angle. Anyone looking from the side will instead see a floral pattern, butterfly pattern, or something else I forget (stars?), depending on your setting. (You can't pick beyond these three because each pattern is physically its own layer it looks like)
This is classic Japanese market electronics. Rather than increase bottom line, add loads of niceties to compete.
My phone was a smartphone, a mobile wallet (osaifu-keitai, tap-to-pay), my train pass (osaifu-keitai is different hardware to android pay, as it works on turnstiles, even when the phone is dead/off, and has been a thing since 2004), a television (over the air!), an answering machine (no messages stored by carrier; the phone picks up if you don't answer and records it to the SD card), had those privacy filter things, and a really responsive camera.
Sadly, it has a non-replaceable battery and refuses to update android unless it can connect to a docomo tower (I think docomo hosts it's phone's system updates on internal network only, not internet). I had to retire the phone long before the hardware gave out.
I'm pretty much stuck with the phone's stock android because A) It's sharp, so the android hacking community hasn't heard of it. and B) I don't think any ROM would have drivers for any of the galapagos features. (especially I need osaifu-keitai, which as well as being a wallet and my train pass, has all of my arcade top scores associated with it (whenever I go, I just tap the phone and the arcade machine looks me up - unlocks all the bonuses I've achieved and my prefs))