There are countless places that you can find claims of a study which found that only 7% of communication is verbal. I’m going to go out on a limb and suggest that since the veracity of that claim cannot be determined, and that it’s difficult to prove that one rule would govern all communication like that, I’m going to go with the more commonly accepted wisdom that while body language and nonverbal communication are important, they are not the end all in conversation.
Most forms of digital communication offer no real recourse to determine intention via body language. Sure, we have asterisk action, but this forces a third person mode upon your conversation, making the character that you speak through a separate entity from yourself. Emojis are another method that attempts to bridge the gap, but even the wide range of icons at our disposal are abysmal in conveying tone accurately.
There are positives to this lack of certain nonverbal cues. If you are communicating with someone from another culture, the lack of vocal and physical cues could be a boon, allowing a flow of information unimpeded by the distraction that body language can cause. As has been demonstrated in a variety of studies (and through misunderstandings resulting from a lack of awareness), not all people speak the same “silent languages”. Most nonverbal cues come through acculturation, not a more standardized training like the written word.
Similar to the idea of anonymity, the removal of body language from interaction can allow for a more unbiased communication. No one need know that you’re a woman instead of a man in a professional correspondence, such as when Linda Sandvik changed to a gender-neutral username at Github, which has it’s share of sexism issues. In this case the anonymity of sorts can provide a sort of cloak of normality, allowing a freer discourse not based on external cues.