what use would i have for a wideband O2 sensor?
 

i've read about what they do and which ones people like, but is there any advantage to me, the casual driver, mr. i'll just pay someone else to tune it?

i searched for a few different things and didn't really see this addressed in what i found.

if you dont plan to tune the car its not going to be a very useful tool to you, the only reason for you to buy one would be to moniter afrs under pulls for that margin of safety. But if your not watching it EVERY single time you do a pull then their probably isnt a whole lotta reason.

on the other side, it is very useful in diagonosing problems.... idle ect.

it will let you know why your engine blew up

Not unless you log the data.