Texting is way easier IMO, especially when talking to bitches. Bitches are annoying on the phone, period. It's easier to text and still go about what your doing. Take your time and reply at your will.
With phone conversations, you have to reply immediately and listen and of course if you don't listen or sound like your not interested, she'll get butthurt. So for bitches, I say texting all the way, especially if it's a "how was your day" convo that normally leads to gossip and other BS if you talk to her on the phone. It's easier to get through the shy ones through text as well. Their more inclined to say something sexual through text, than with their voice.
I'm talking to some bitch right now and we just mostly text. It helps, good tool.