I've favored Bianca in my decks where I ran 4+ of cards that depleted my hand, such as Ultra Balls, Computer Search, etc. I found Bianca to be an excellent card draw source to replenish my hand (without the need to discard additional cards) thereafter. However, I've also had numerous situations where I had just a lone Skyla or no card draw Supporter in my hand; so, I could the Skyla to get a Bicycle and draw some cards.
I now run at least 2 Bicycle in all my tournament decks. I also no longer run Bianca either. Between Bicycle, Colress (has made a big impact), N and Professor Juniper, I do not find enough value in using Biancas at this time.