Most plated bullet are first produced via swaging from pure lead, then plated afterward to end up up with a bullet the same diameter as that of a jacket bullet.  So you have a think copper jacket, over a pure lead bullet, and this will not only limit the speed that the bullet can be pushed to hold onto the rifling, but on some bores, end up with the bullet not fully sealing off to the bore initial as well.

With PC bullet, then are casted out of lead in the 16 hardness range and slightly over sized to start with, PC coated, then sized in the end .001" larger than a jacketed bullet.  So what you get, a bullet's hardness that will hand onto the rifling, slightly larger to seal off to bore in initial embed, and not only does the PC coating prevent leading, but you gain about 35fps speed of the bullet from the PC coating as well.
Hell, with a cast bullet  Brinell of 16 or greater, PC coated, you can push the bullet over 2K with out fear of leading, losing grip of the rifling,  nor needing a gas check as well.  Hence cast bullet will go faster than jacketed or plated bullet with the same amount of powder, and then your gaining about 35fps on top that with the PC coating.  So when your loading for a MPF of 166, your using less powder per bullet isntead.

As for why most of use cast and PC our own bullets, it more than just the cost saving, but allows up to size the bullets to the needed diameter for the barrel bores as well.   Take a 9mm production barrel that the bore is supposed to be .355", and will find that the bore may be in the .356~.357 range isntead.  So to get the barrel to really sing, we size the bullet .001" over the actual size of the bore, and this allows for the best embed and seal of the bore as the bullet is moving down the barrel.

Worse, take marlin 44mag rifles with either micro groove or Ballard rifling, and although the bore should be .429", will find due to the bore size and even rifling type, a Cast PC bullet has to be .431~433" to get these barrel to print best with a cast bullet instead.

As for if you are going to get into casting for USPSA, then always cast a truncated bullet.  
The shape of the bullet nose will cause the least amount of feed problems.

Yes this thread asked about coated bullets which are different from powder coated bullets.

Never shot a hitek bullet, but I have never found the upper end where a powder coated bullet will fail.

I shoot 357 and 44 mag with full loads of H-110 cast from WW's. Not sure if that's what you mean by "hotter powders and higher velocities".

I'll echo the others, other than hollow points for hunting or carry, coated is almost all I shoot.

Yep, the PC coating does get burnt slightly when the bullet is shot, but the rifling fouling does not build up to a point that is going to cause accurately problems in the barrel isntead.  Truth is, when you go to clean the barrel, the Coating fouling is easy removed with the first pass of a patch/brush with standard cleaning agents like Hoppes isntead.

On plated bullets, you get copper rifling fouling as well, and that fouling take a little longer to remove with something like sweets isntead.

As for the PC type fouling in comp guns, the quick way to remove that fouling is with something like Acetone instead.  Hence the fouling is not so much bonded to the metal like you get with copper plated bullet fouling, so the acetone works quickly to break the PC fouling down from itself, to release quickly from the metal parts as well.

Also to add, PC bullets are not completely  smoke free, so you still get a slight hint of smoke still.  
In say unlimited 9major comp pistols, it not the fouling in the comp that reason that I don't run PC bullet of a hardness of 18 or higher, it's the smoke from the comp directed upwards into the scope plain that slows me down instead. Hence even with dust shields on the scope mounts, the PC fouling does start to dust up the front of the red dot lens on the quick side before you are completed with the run.  If you are shooting into the sun, this can cause some problems with fouling causing less then perfect sight pictures through the Red dot even half way through the run.

To add where, whether the thermoplastic or a thermoset polymer coating is added through powder shake, or acetone liquid mix, its still a thermoplastic or a thermoset polymer that is going to get burn/produce small amounts of fouling as the bullet is being shot through the barrel.  With the shake method of coating, the glitch with heaver fouling is the fact that the excess coating may not have been shook off the bullet before baking, leaving more than needed polymer on the bullet to be burn off in excess isntead.