Political scientist and aeronautical engineering graduate, Associate Professor Stephen Hoadley, said the aircraft would pay for themselves in the long run.
But much of that pay-off came in intangible terms like international credibility which was hard for Treasury accountants to measure, Hoadley said.
"It makes New Zealand interoperable with the Five Eyes partners, from whom New Zealand gets a lot more intelligence data than it provides."
Hoadley, from the University of Auckland, said the P-8A could enhance New Zealand's surveillance skills in the South Pacific and potentially relieve some pressure on Australia.
"It's a fortuitous and logical division of labour," Hoadley told the Herald.
He said the training could also help RNZAF staff work better with allies in years ahead.
"It makes the individuals who learn to fly the aircraft also interoperable."
He said when allies knew how to operate each others' aircraft, pilots and other staff could be seconded to other countries if needed.
Hoadley said Chinese expansionism in the South Pacific presented another challenge.
He said Beijing used a "highly-subsidised and semi-official" fishing fleet to gather information and increase its influence in the ocean.
"It's expanding its operations in the South Pacific all the time. These aircraft will be able to keep tabs on them."
The Orions would be useful in anti-poaching operations, Hoadley said.
Mike Yardley, Ministry of Defence Deputy Secretary for capability delivery, said a simulator and classroom training suite Boeing provided in the deal was important.
"The simulated environment allows for crews to be trained to fly in more diverse and challenging scenarios," Yardley said.
"The suite is also a safe, economical and environmentally friendly way to train personnel."
He said funding for the US$109 million training suite came from within the NZ$2.3 billion budget for P-8A Poseidon fleet, already announced back in 2018.
"The Royal New Zealand Air Force already use a range of simulator suites for training, including the NH90 helicopter and T-6 Texan Aircraft," Yardley added.
Boeing on Wednesday said the US Navy awarded it the Foreign Military Sales contract to provide training for the Poseidons.
The contract included a weapons systems training programme.
The company said it would prepare the RNZAF to operate and maintain "the world's premier maritime patrol and reconnaissance aircraft for decades to come".
Boeing said all training for the new aircraft would eventually happen at RNZAF Base Ohakea, near Palmerston North.
Aerospace analysis website Shephard Media said initial crews were training in Jacksonville, Florida.
Training systems were expected to be installed and ready for training at Ohakea in January 2024, Shephard added.
The new aircraft were bought to replace Orions which entered service in the 1960s and were upgraded in the early 1980s and given the P-3K2 designation.
The P-3K2 this year conducted patrols supporting New Zealand Customs and surveillance flights to report on damage Cyclone Harold caused in Vanuatu and Fiji in April.
As the national coronavirus lockdown neared its end, one P-3K2 conducted surveillance for police of recreational boats in Auckland over Anzac Day weekend.
The ageing aircraft's replacement was discussed for years before the $2.3 billion deal was signed.
At one point, Parliament's Foreign Affairs Defence and Trade Committee considered replacing the Orions with drones.
Last month, Forbes reported that the new P-8A Poseidons might be able to locate submarines from the air thanks to a "radical" new Raytheon radar system.
