My work environment is very noisy, so it makes having a conversation with someone over the phone very difficult. Texting works as it's a quick form of communication, plus it leaves a nice breadcrumb trail to follow back.
Plus it helps I have unlimited texts versus limited minutes with my calling plan. However, I know most people don't have similar arrangements so I try to be responsible about the frequency of texts I do send out. You won't find me sending out 10k messages out like you see some kids. And mine have complete sentences, with grammar and correct spelling!