The PH180's have just about the best circuit breakers of any transformer right out of the box, and they are practically as good as any other option at any price. Good enough that you don't have to worry about adding any "better" circuit breaker.
That said, there are two things to consider. First you will want to use the TVS diodes on your layout. These prevent spikes of high voltage from damaging the electronics in your engines. The easiest method of using these is to add one at each point where you have feeder wires attached to the track.
The second thing is making sure your track wiring is good enough to use with a 10 amp circuit, as supplied by the PH180. You'll want to use AT LEAST 16 gauge wire, and even that is skimping a little more than you should, but the breakers in the PH180 should go off before you do much harm. 14 gauge or thicker is probably recommended if you are following the "star wiring" scheme for DCS, as only one wire is supplying all the power to a given block in that method, whereas in standard wiring the track receives power from more than one point, splitting the load between multiple wires.
If you only have smaller wire at the moment, and don't want to replace it with 16-14 gauge, you'll want to place a circuit breaker in line after the transformer to limit the current to 5 amps or so, so as to eliminate the possibility of damaging the wire with a short.
Fuses are not usually a good investment for track protection, as the costs add up quickly if they blow every time something derails. Circuit breakers are usually a better investment in the long run. Fuses are more practical in cases where the fuse is used as circuit protection of last resort, in a case where it is not likely to ever blow, but is nice to have the added safety in case of an uncommon short. I don't see any need for a fuse in the set-up you have described, however.
As long as your wiring can safely handle the full 10 amp current that the PH180 can provide, you should be good to go. Plus TVS's to protect your electronics. Worth noting that some folks recommend that the TVS built into the DCS TIU is adequate protection, or that it is a good idea to use the TIU for this protection. While it will offer more protection than having nothing, the TVS in the TIU is there to protect the TIU, not your trains. These devices work best as close to the electronics they are intended to protect as possible. a spike of high voltage electricity will take the path of least resistance, so if it is easier to go through your locomotive that all the way back through the wiring to the TIU, than through the engine it will go. The optimal location for TVS diodes is to be installed inside each engine you want to protect, however this is a bit complex for a lot of folks, so placing them at each feeder makes the most sense as far as ease of installation verses amount of protection for most users.
JGL
