Prize money and commercial opportunities are significantly lower in the other European competitions.
Uefa's financial report shows that Arne's Slot's side earned 98.1m euros (£85.3m) in distribution payments for reaching the last 16 of the Champions League in the 2024-25 season.
When Liverpool were in the Europa League in 2023-24, they got just 26.8m euros (£23.3m) for getting to the quarter-finals.
Winning the tournament would help bridge the funding gap a little more.
Tottenham received 41.4m euros (£36m) after lifting the Europa League last season, but Chelsea were paid just 21.8m euros (£20m) from the Conference League.
Maguire said that the loss of money from Uefa would only be part of the story.
"It also has an impact upon matchday receipts," Maguire said. "It has an effect on the broadcasting money.
"It will mean lower commercial revenues, because there will be bonuses embedded in contracts with senior sponsors."
At the high end, Maguire thinks being out of the Champions League could in total "cost Liverpool around £120m".
Liverpool splashed out more than £400m last summer, signing players such as Florian Wirtz and Alexander Isak.
It was the biggest spend by a club in a transfer window.
But Maguire says that Liverpool "are extremely well run". One season outside of the Champions League might not have a huge effect, he said.
Last week, Liverpool announced record revenues of £703m for the club's most recent financial year through to May 2025. The club returned a profit of £8m.
Even with last year's signings, Liverpool are only eighth on net transfer spend over the last five years.
"While they did have a significant transfer outlay, you've to take a long term view on their spending," Maguire said.
"It's still substantially behind the two Manchester clubs and Chelsea in particular."
Uefa's latest benchmarking report says that Chelsea made a pre-tax loss of £355m for 2024-25.
Manchester United's finances are improving but the club's debt is now approaching £1.3bn.
Will Liverpool have any problems when it comes to complying with financial rules?
"The simple answer is no," Maguire added. "They're very forensic in terms of their financial analysis."
Being out of the Champions League could of course affect the players they might attract to Anfield.
For Van Dijk and for Liverpool, being in the top competition will remain vital regardless of money.
