Tempted by the offer being open to existing subscribers, but seems odd they are selling a 4K/HDR supporting device, but not offering a 4K based plan!
> You may apply the value of the offer to a different Netflix streaming plan.
From the terms of the offer, it does look like you can apply the value of the offer to a 4k plan at a reduced duration.
* Offer value may be applied to a different Netflix streaming plan under the same account; exchanges in this manner may alter the duration of the offer. Netflix price plans subject to change and the duration of the offer value may be prorated accordingly.