Crotty marked his first appearance since sustaining a broken thumb in the Crusaders' Super Rugby semi-final victory over the Hurricanes in June by touching down twice as the All Blacks sailed to victory in their final Rugby World Cup warm-up.
George Bridge scored four tries, Ben Smith bagged a double while Sevu Reece, Codie Taylor, Kieran Read, TJ Perenara, Matt Todd and Ardie Savea also got in on the act on Saturday.
Hansen had planned to limit Crotty to 65 minutes and stuck to that decision despite having already used all of his replacements.
"It was a good opportunity again to put ourselves under a bit of pressure when it comes to how many are on the park," Hansen said.
"We could have left him on, but Ben [Smith] came off because he was a bit tight in the hamstring, Beauds [Beauden Barrett] had already come off.
"We could have put Aaron [Smith] on the wing, but we were happy to put Aaron on for TJ and then of course we realised we wanted to take Ryan off at 65 because he's just come back and hasn't played for so long.
"He played 40 last week [in Canterbury's 80-0 Mitre 10 Cup victory over Southland] and 65 today and will be good to go in a couple of weeks.
"We could make a choice, and the scoreboard said we could make that choice without too much risk."
New Zealand begins its Rugby World Cup campaign against Rugby Championship winner South Africa in Yokohama on 21 September and Hansen felt the dismantling of Tonga was hugely beneficial to its preparation.
"Everyone got a run, and no injuries. We played some good footy and got the opportunity to just cement some combinations again, and finish a good week's work," he said.
"We got rugby time. We got collision time, we got set-piece time, we got time on the ball under pressure, and time on the ball in open space.
"That's what rugby's about, and we play a massive game in two weeks. If we didn't have any of that today, then we would have been in a lot of trouble. We got exactly out of it what we needed to get out of it."
Hansen will leave his post at the conclusion of the Rugby World Cup but was not feeling emotional about having overseen his last All Blacks Test on home soil.
"Clearly, you know it's your last game, but are we dwelling on that? No, [we are] trying very hard to stay focused on what we're trying to do, which is coach a team to try and win a third World Cup [in a row]," he said.
"When you retire you've got plenty of time to reminisce about all the stuff that's gone before you and pat yourself on the back or give yourself an uppercut depending on how things go."