[throwanem]

Text as a Siri interface has been available for a while now. Long-press the sleep/wake button to raise the prompt.

[rcdemski]

It has, but it’s presently an accessibility affordance you have to enable first. It’s found under device Settings > Accessibility > Siri > “Type to Siri” On/Off

[throwanem]

Oh, go figure. Let that be a lesson: if you don't check out the accessibility options, you're missing at least half the cool stuff your phone can do to actually make your life easier.