Gigs_98 said:
There was already a little discussion about that in the "tour de france route thread" but I will write it here again.
I think time bonuses support attacks on the last few kilometers of a mtf.
Let me make an example:
Chris Froome wins every single mtf after an attack from only 1 km before the finish, but each time he wins only by 15 seconds on nibali, who gets 2nd. Nibali however isolates froome on the glandon which leads to a big time gap between these two and at the end nibali wins with 1:30 advantage on froome who only gets 4th because he has to make most of the work. Now lets say there are no time differences between these two in the other stages which would mean nibali would win in a tour without bonus seconds while froome would win by one second in a tour with bonus seconds.
I know that example is extremely far fetched but here comes the point: Normally you have to make long range attacks to get a big amount of time on your rivals (which is definitely more exciting to watch). But you can't do long range attacks on every hard mountain stage because you have to spend much energy for that --> you can't win every mountain stage with this tactic while you can with the "attacking from one km to go" tactic. So because of time bonuses the more boring tactic gets supported.
There are pluses and minuses to both points.
For example, the 2009 Vuelta was killed by the time bonuses, because Alejandro Valverde had the maillot oro from the end of week 1 onwards. Because Valverde was stronger in the sprint for the line, the opposition did not work to chase breaks and go for the stage wins because if they didn't shake Valverde he'd add to his lead by picking off the time bonuses after following them, which as race leader he is obviously entitled to do. With the tame ending to the race, Caisse just let the break go over and over again and nobody chased it down because of the fear of Valverde adding to his lead, with the TT the only chance to pull back on him.
However, at the same time, the Tour was hurt by not having time bonuses, because the lack of time bonuses combined with the awkward design of some of the mountain stages meant that the stage wins ceased to be of interest to major contenders. For the whole of week 2 you had Ag2r with the maillot jaune that they took because Astana and Saxo had no intention of chasing down the Brice Feillu break on one of the very few mountain stages that year, and the breakaway went, unchallenged. The break took most of the main stages, including the Mont Ventoux shootout that the ASO had staked the race's excitement value on. There was no incentive for the main contenders to be up at the front, and therefore there was no incentive for them to put early pressure on in the stage to make sure they could haul back the break, meaning legs were less tired, meaning gaps were fewer, and only really the excellent Le Grand Bornand stage saved the race.
Whether the time bonuses aid or hurt the racing really depends on who has the lead and what the design of the race is in order for others to feel like they can dethrone them.