One cannot lose sight of the fact that these are "dangerous game" loads, not for whitetail deer or hogs. Lessons learned on thin skinned game are often not even relevant to the heavy stuff.
The advantage is that they do not deform, at all. They can smash through heavy bone and muscle and penetrate through the vitals without any deformation whatsoever. Any amount of deformation is going to negatively affect penetration. Proponents of cast bullets have succeeded in creating a few myths. I believed them myself for a long time. Cast bullets do not have to be run too fast to deform. They can deform at virtually any useful velocity. This is not to say that they do not work, because they do, within their limitations. Problem is those limitations have often been minimized, if not completely ignored.
Cast bullets do work well at lower velocities and a good many critters have fallen to them but this idea that 900fps is all that's needed is simply false. Greater velocity increases tissue damage and penetration. That is, until you run into the limitations of the material, where you start losing penetration due to deformation. Which is where the monolithic solids come in, because they can be run at any speed and still hold their wad.
Weight is turning out to be much less critical than we believed. It is important in cast bullets because you need momentum to overcome the effects of deformation. The monolithics are able to do more with less weight. You still need enough weight to get the job done but it is less critical than with cast.
These were recovered from an 1800lb longhorn bull. This is my favorite 355gr cast bullet from Beartooth. It did the job. It broke shoulders, destroyed the vitals and also did not exit. Even at 1200fps, the deformation is undeniable. The bullet on the far right sheared 20gr off its weight. The longhorn is long and lean and nowhere near as wide or as tightly constructed as the water buffalo below.
These bullets were recovered from two 2000lb water buffalo. The Punch bullets could be reloaded and fired again. The hard cast, not so much. Several of the Punch bullets exited, despite being ~80gr lighter.
I'm still a big believer and user of cast bullets. I just work within their limitations and know that they are not fail-safe. They work very well, even on bigger game but are simply not the
best tool for the job when the quarry can stomp, bite or gore you.