R6220 Flashing and reverting


I am thinking about flashing OpenWrt on my Netgear R6220, i am not sure why, but i think its a discontinued product and i might aswell flash openwrt.
I do not have much settings, but i want to make it as painless as possible for my connected devices.

  1. Is flashing the firmware through "Firmware update" 'pretty safe'? I am connected through cable.
  2. Can i activate wi-fi and set same SSID + Passwords as i currently have, and my devices will gain access like "nothing changed"?
  3. Can i revert the installation and go back to stock, cause then i can easily upload a backup-conf and act like nothing happened :).

And, finally. What is the best reason (except freedom!) to install openwrt?
Thanks for taking your time to read/answer.

Please read the Wiki: https://openwrt.org/toh/netgear/netgear_r6220#installation

Yes, you configure the same SSID and passphrase under Network > Wireless. WiFi is disabled by default.

So, nmrptool for stock firmware? Cant be done with "openwrt firmware upgrade"?

This nmrptool, is it supposed to show the Router's ip+mac, or the current machine?

Cause, the tool on 2 different computers show different output... the current machines local ip. I just wonder if its supposed to be like that.