Don't forget your basic stats -- if you might get a bonus 1/4 of the time, that means on average two of the eight nodes would have given you extra XP. However, because we're talking statistics, it's perfectly reasonable that all eight votes might give you extra XP, or (as happened) that none of them give you XP.

Basing your conclusions on four days of eight votes each is too small a sample size.

While XPs may not be a BIG deal ...

No, XP's not that big a deal. I'd happily go back to zero and start again. What's more important is how much I continue to learn here, even after two years as a member.

What's valuable here is the journey, not the destination.