User blog comment:TheTobarMethod/The New PBE/@comment-9369480-20131022215516

The PBE was never meant to be a "test realm" so you could tool around and try new champs and new items with no penalty to your account. It has always been intended to be a test realm to find bugs, graphical errors, glitches, and problem areas with champs, items, or maps.

If not for the PBE, it is unlikely that RIOT could have fixed the Twisted Treeline map, where there was a hidden item in the spawn pool. Darius, Syndra, Blitz, and Thresh could grab this "item" and block pathways with an invisible block.

If not for the PBE, there would be lots of bugs that we'd see. Without regular players noticing bugs and glitches, all these problems would be seen on the live server and people would complain about RIOT being lazy or something. People use the PBE to give them good feedback on what problems they have seen or what changes they enjoy or dislike, and why.