is converting key manditory?

does everyone have to convert there game key to steam key?
i hope coveting to steam is not mandatory
i don't like steam

No, you don't have to at all. And it appears that the non-Steam version runs better occasionally, so...

It is not mandatory.

A lot of people use Steam, so probably the majority of people have done so.

lets say 2 persons, x and y had PA Game keys each
x converted to steam
y did not convert to steam
can x and y play together?

Yes, both will be play though UberNet.

Steam only used for authentication.

How about if you convert your key to Steam, will you still be able to play it via the launcher free of DRM via the independent Uber launcher and icon?

thanks,
Yngvald

You'll able to play though launcher, but it's won't be DRM-free anymore. E.g for example if your profile on Steam banned most likely you'll lose UberNet access as well.

Also when you convert you key to Steam your access to PA will be revoked from UberNet account, but when you run it though Steam first time your accounts will be linked and you'll able to use launcher again. But then technically you'll be Valve customer.

You say that I'll still be able to play via launcher, but would this from that point require Steam to be launched at the same time?

No. You don't need running Steam if you run PA though launcher.