Noctua may not want to say it, but it feels safe to assume their Redux series of fans came about as an answer to those questioning why their products are so expensive. They could have just named these fans something else entirely, but decided to own up completely by stating that the redux series fans had been developed before, and a different color scheme was given to also offer something to those not fans of their tan-and-brown-colored fans. Cut down on accessories included, have a simpler packaging style, use these fans that have been in the market in one form or another, and you now have a fan series that is more affordable. They are also not going to have the latest of Noctua's innovations and technologies, and this did hurt initially when the first entries to the redux series were not necessarily very good for watercooling or similar high airflow impedance situations.
The entry of the NF-P12 series into the Noctua redux product line does a lot to help change that, however, given this is a good fan to begin with when it was in their standard lineup before. The NF-A12x25 we saw before absolutely outperforms it at the same noise levels and will get most of the attention from consumers, but the NF-P12 redux series is a sleeper of sorts, especially at the ~$14 price point. Sure, it has no RGB lighting (nothing from Noctua does) and is really taking the minimalist approach to heart as far as packaging and accessories go, but if you want a well-performing, durable fan backed with 6 years of warranty and customer support, you have a solid option on your hands now.