Of course you are right - but...
First reason to me to replace all tubes is that I think that particular one wasn't exactly dead as I had no loss of sound or power whatsoever.
So I assume that it simply slowly degraded as kind of its normal ageing process.
As all other tubes have the same age and usage profile I fear that they also might go down one after another sooner or later.
Second one - I wanted to know what the amp would sound like with (probably) better tubes.
So I replaced all 5 preamp and 6 poweramp tubes with the JJs, I was a bit back and forth between 6550 and KT88 but finally decided to stay with 6550s for the moment to make sure that sound differences would actually come from the brand of the tube and not from changin to a different tube type.
Two conclusions by this time:
First - Infinium seemed to do its job perfectly in my case, heard lots of people complaining they wouldn't trust it...
It marked one tube red after some minutes of playing, switching the amp off, having it cool down and powering it back on resulted in the LED going red again after a moment.
Swapping tubes between sockets made the red LED also change to the socket where the defective tube was plugged in.
After having replaced all tubes no LED was lit anymore, they went back to flashing one or another every few minutes indicating that the BIAS was readjusted during operation if needed.
Second - sound wise the original Bugera tubes are not really bad, but switching to JJs added a bit more of warmth, clarity and bottom end.
So for all you guys out there with the first set of tubes still in the amp - don't worry there's no reason to throw your money out of tha window as I already did that for you.

Just stick with the original tubes as long as they do their job.
But when the day comes that they all got old and need to be replaced it definitely makes bit of an upgrade to switch to well known brand tubes.
Next time I'll try KT88s, so expect an update in this thread in 5 years or so...
