F2P 8x Chromium Pull worth it?

Really depends the risk you are willing to take. You can get lucky and pull a great character...or end up with a bunch of shards and possibly a 1* or 2* character...or no characters. Nothing is guaranteed, and you can get shards or character (mostly shards) or any character - 1*-4*, so it is truly a gamble. That being said, I've done it a few times. I've only pulled 1 or 2 characters that I specifically wanted, but haven't had a terrible draw either.

I guess you just have to ask yourself - am I okay with spending these crystals, knowing there's a chance I could end only up with a bunch of shards for random characters?