Hi Millwall.
Good question, actually. The idea behind the wedges is that they will generally give you more loft (i.e. upward flight from the time you strike the ball) than other clubs. The 54 goes higher than the PW; the 60 goes higher than the 54, and so on. There are other loft variants available as you progress in the game as well, but those are the two standard lofts.
The other part of the equation is distance. If you hit a ball with the same power, the ball that goes higher will also travel less distance, so it becomes a trade-off between getting it "up" and getting it "out there". My PW goes around 100yds, my 54 wedge goes about 85yds and my 60 wedge goes about 65yds. All with the same power.
The choice of which club to use comes down to essentially three things: (1) how far I need to go, (2) what's in front of me - e.g. a bunker or some rough - and (3) what my ball is resting on - e.g. sand, rough or fescue. As a rule of thumb, the worse the lie (i.e. rough or fescue or sand) the higher the loft you'd need to clear it - always assuming you're not looking for major distance. Sometimes you just need to chip out of some trouble onto the fairway and then have a crack from there.
So to your question: yes wedges are good in most cases for getting you out of tricky situations, but this will not always get you in the green. Also, they are good if you have a short shot to the green within the range of your wedge. As it goes higher, it also comes down straighter and stops quicker than a club with a flatter trajectory so you have a better chance of keeping it on the green.
That's the theory anyway. The best way to put it to the test is to have a crack and figure out what works for you. Good golfing.
RNE