First, it’s asynchronous. We don’t live in the 1990s any more, so email doesn’t beep for attention. The understanding is that if you send an email I will respond at a time that is convenient to me. Instant messages ping because — well, instant, right? And while I could switch off the needy noises from text or WhatsApp or almost anything, that would mean stripping the technology of a genuine use case in order to deflect some of the annoyance of people misusing it.