Just because my giant-hating Dwarf wants to go and bash some giants doesn't mean his attention won't be severely diverted for a few glorious hours if on the way to the giants he notices that he's passing a room full of undefended gold coins!
Now, wait a minute... You guys accused us of RAILROADING the party because we glossed over the trip to the giants, but WE GAVE THEM A CHOICE TO DO OTHER THINGS and they said "no, go to the giants", and now I have to give them YET MORE choices of different things to do when they ALREADY told me EXACTLY what they wanted to do and had a chance to do something else! I don't accept this judgment, I don't even accept that it is a reasonable or fair characterization, AT ALL! Can you guys at least understand why that would be?
On the odd occasion I'll drop in some power-up stuff kind of like what you did here; on other occasions, particularly if it's levels they need, I'll lob a side-trek adventure in their way and see if they bite.
I think lootz play a quite different role in different games, so its certainly not like there's a 'right way' to do it

With 4e's style of system certainly there's less of a need to cast it in terms of strictly a 'reward', although gear CAN be a goal. A character in my 1st 4e campaign had a goal to find a certain weapon. Actually the goal was to find the maker of the weapon, but finding the handiwork was very interesting in its own right to her, and the item later explained several plot elements.
That's exactly right! Maybe there IS something else they'd rather do instead...but they won't ever have the chance to unless you... ...do this, by making mention of anything interesting they pass during those 30 minutes.
NO NO NO! We already gave them the choice to 'do something else'. The players could have even MADE UP that something else, in effect, by just pursuing some other interest. There's no need to keep constantly dangling one distraction after another when the players have already signaled what they want to do. Its not even just silly, it gets actually obfuscatory and even rude at a certain point if the GM won't just GET ON WITH IT!
Chances are they'll still go on to the giants, either right away or later, but if they find the slimy passage or the room with the knight's skeleton nailed to the wall more interesting on the way, let 'em at it!
Again though, if the players want some dungeon crawly "lets wander the Underdark in search of fun" they can say so, we gave them the choice of 'other stuff'. If they ask "has anyone heard of any interesting areas to explore" or something like that, I'll happily oblige them, although I'll work in things one or more of the players have shown interest in before.
So, a skeleton nailed to a wall sounds fun, maybe someone asks about finding the grave of the legendary Sir Mallory! Again, the players are partners here, they're free to make history checks or whatever to generate inputs that can generate new framing.
Fundamentally we just have, in Story Now, a streamlined way of introducing content. Instead of long and often tedious sequences of blundering around in lots of side passages hoping to find the 'interesting thing' they want, we figure out what that is, mechanically create the possibility that it will exist in the fiction, and get to it.
Just because the players say the next event they're interested in is the giant's cave doesn't mean the giant's cave will be the next event they encounter...or that the intervening encounter won't end up being even more interesting...or less; you don't know until you do it.
But I DO know it. Because it was told to me outright by the players, 'go to the giants now GM'. POSSIBLY the GM is so clever that he's made up something even better to put in their way, but then why were the giants even there? If they're not that likely to be interesting to the players they probably wouldn't ask, and the GM (me) would presumably go on in some other direction.
Admittedly, Story Now is NOT about the GM throwing random stuff at the party that he just thought of or rolled on a table or whatever. There's no denying that. I'm asserting that those techniques don't generate the same sort of story as going to the action does. Its fun! Other things may be fun too, matter of taste!