I think the better question is why should I bother with Wire? It's all of 3 months old, (and iOS is already on 2.0? Really?) Signal has been around for a few years now and uses a well-respected ratcheting encryption library similar to OTR. It's been well-audited and widely-adopted. It's already the de facto standard for FOSS E2E mobile messaging.
They seem more friendly and open than the Signal guys. They're using similar encryption, go check out their GitHub for more info. It doesn't require a phone number and has multi-device encryption with desktop support. It has audio, video, pictures, sketching, likes, editing, deleting, groups, and more. Signal feels like a joke in comparison. Try it.