I appreciate the flexibility but, in practice, I barely ever change dates on award tickets. For one thing, as time progresses, availability in redemption classes on alternative flights is often not there. Also, I often book non-cancellable/changeable accommodation at destination so I would stand to lose quite a bit if changing dates, which is a disincentive. As kt74 suggested, it is not fundamentally different to booking a discounted revenue ticket. Sure, there is a risk (and the risk is higher with award tickets since travel insurance will not pay back) but that does not necessarily make it fundamentally unattractive.

I do have some award tickets which are more speculative and which I do cancel more readily (not so much using DC but using BAEC since cancellations are costless as a gold). These are often short-haul "insurance" bookings which I often cancel when my plans are clearer and I can find a revenue ticket alternative at a price which is still acceptable. Clearly, I would not use an FFP like A3 for those kind of bookings. For my ordinary award bookings, OTOH, why not?