This is the epitome of a Swifty approach.
The vast majority of Swift programmers do not need to control lifetimes. The language lets them go about their business without being burdened by lifetime annotations. In those rare situations where the design depends specific lifetime behavior, programmers can express their intentions. That's important not only to verify assumptions but to communicate to other programmers.
The move intrinsic is complementary with a near-future @noImplicitCopy annotation along with other lifetime controls. They're being introduced in the order that it makes sense to develop them and get programmer feedback. Naturally, that tends to be in order if increasing importance. If you find yourself saying "I won't use this control, but would like the next one", then that's reasonable and expected.
We're starting with niche tools now, but they are an important steps toward introducing move-only types, which will be a much more visible language feature. Move-only types build directly on top of these controls and will inherit their semantics. Being able to experiment those semantics earlier means that the design of the larger feature will be better when it is introduced.