This is a deal that everyone expected soon and so Everton confirming the sale of the 22-year-old star is of course not a surprise at all.
It was almost a certainty that Onana would leave the Blues this summer although there had been only cursory interest from other clubs and nothing concrete had happened until Villa stepped in last week.
Of all the players the Toffees were willing to consider selling as they tried to balance the books and avoid a possible third PSR breach, the Belgian was the most likely.
His departure from Goodison Park brings in much-needed cash and important breathing room - as it was always untended to do - more so now after the news on Friday that the proposed takeover by The Friedkin Group is off.
With the American group pulling out, Everton are potentially in greater need of that money than might have been the case had the takeover been successful, and if it had gone through relatively quickly.
All that was far from certain and anyway once a big enough offer came in for Onana he was going to be on his way regardless.
In one sense it has to be with regret that the powerful Belgian midfielder is departing Merseyside. In another however, this looks a good deal for all parties concerned.
Although he physical attributes and ability were at times clear to see, too often he had flattered to deceive in an royal blue shirt and had become an increasingly peripheral figure towards the end of last season.
Onana had rarely started for Sean Dyche in the final weeks of the campaign despite the Blues having one of the Premier League's smallest squads and being desperate to move away from the relegation dogfight.
Most tellingly, he was not a starter for any of the three matches which decided the outcome of the Toffees season as Everton beat Nottingham Forest, Liverpool and then Brentford in consecutive home games to secure survival again.
However, it is still a little to be regretted that the Blues have been forced again to sell a talented young player for what is probably under his real market value.
A similar thing happened with Richarlison two summers ago when the Brazil striker left for Tottenham in a £60 million deal with immediate financial pressure hugely important than too.
Still, I think virtually all Evertonians would agree that it is better Onana leaves if the club can then have a better chance of holding onto Jarrad Branthwaite for another season at least.
With his leaving though the Toffees need another defensive midfielder to replace him, and if the rumours are to be believed than Kalvin Phillips will likely be that player.