Betts, who will play in the second row for Great Britain in the World Cup final against Australia at Wembley this afternoon, has become the player without whom neither his country nor his club, Wigan, would dream of turning out. Therein lies the trap; the game of rugby league is simply asking too much of him and he may not be able to deliver indefinitely.
'The one worry with Denis is that he plays too much football,' said the Great Britain manager, Maurice Lindsay, who, as chairman of Wigan, brought Betts into the professional game as a 17-year-old.
'We had a tip-off from a scout when he was 15 and playing for Leigh Rangers. I went along to see him and I was impressed by the way his mum was the one who gave him his half-time rollicking.'
Betts had come into rugby league by an indirect route, growing up in a part of Salford which, despite the proximity of a professional league club, was strictly football territory. He was good enough at that game to be on schoolboy forms with Manchester United, but a teacher spotted his greater potential in the other code and steered him in the right direction.
'When he signed for Wigan, he said that his ambition was to be able to provide for his two-year-old daughter. Everyone thought he was joking, but he wasn't,' Lindsay recalled. Betts, a quick developer in all respects, is now married with a second child on the way, and providing for the family should not present too much of a problem.
In six years, he has developed into the epitome of the modern second-rower. His pace has always set him apart, but long hours in the gym have built up his physique without blunting that speed.
'He's built his own body,' Lindsay said, while his coach at Wigan, John Monie, thought that people would be 'surprised to see Denis without his shirt on, to see just how big he is now'.
In a sense, the strength that Betts has acquired has become the greatest threat to his continued excellence. Players in a game as physically punishing as rugby league need to recharge their batteries from time to time. Their bodies tell them when to do that by shutting down on them.
Betts is different; he does not miss matches, and the sheer weight of the workload that imposes on him could prove his downfall, some fear.
On tour this summer, for instance, the real Denis Betts, the devastating wide runner who can break the tightest defence, was rarely seen. He worked as diligently as anyone, but the vital spark was somehow missing.
'Of all the players who went on tour, Denis was the only one who had played every match of the previous season,' Monie said. 'His workload had been heavier than anyone's, so it was no wonder that he sometimes looked tired.'
Betts returned from tour to go straight into pre-season training with Wigan, so it was less than surprising that he still looked jaded when the domestic campaign began.
'There was some confusion in his mind about whether he should be taking a break or doing a bit more and that affected him,' Monie said.
But then an astonishing thing happened. Denis Betts missed a couple of matches; headline news in itself in Wigan. The injury or injuries that kept him out were variously described. 'It was an accumulation of things,' Monie said. 'Thumb, finger, the back of his hand . . . ' And so on, over most of the terrain of the apparently indestructible Betts physique.
The break refreshed the parts that other methods could not reach. At the same time, Betts resolved a simmering argument with the club over improving his terms to something more appropriate to such a key player.
'I got my desire back,' he said. 'I realised that was what had been missing, and you can't play this game if you're the slightest bit half-hearted.'
Betts now recognises that he runs the risk of burn-out, and wishes that the English season did not require him to go out and put his body on the line quite so frequently.
Adding extra games to the calendar - even glamorous ones like Wigan's World Club Challenge against the Brisbane Broncos next Friday - is not something which brings whoops of joy from the Betts household.
He has been outspoken about the Lancashire Cup, a competition which, he believes, merely adds another series of largely meaningless games to the already overcrowded season. Ironically, he then went out and won man-of- the-match honours in the Lancashire Cup final against St Helens last Sunday; not for his trademark wide running - it was not that sort of game - but for his tireless work down the middle in both attack and defence.
Monie rates his form in that game and the First Division match against Leeds the previous week as the best he has seen from Betts. That bodes well for Britain this afternoon, because Betts at full throttle is a player who can disorientate the best-organised defence.
A sport that has been asking far too much of him needs him to come up with the goods once more.