and realistically a hot 44 can put out as much energy as a 454 (BB's hottest load).
That is a less than accurate statement. While it may be true that that particular load produces energy levels approaching the Buffalo Bore loads for the .454 Casull, it doesn't tell the whole story. The Buffalo Bore loads for 454 are well below what the cartridge is capable of within the SAAMI pressure limits. The .44 load however, exceeds SAAMI specs by what is likely a significant margin.
If you look at the load data for .454 Casull on Freedom Arms' website, you will easily see this. One example is a 300grn jacketed bullet at 1750fps from a 7 1/2" barrel. If energy is the number you like to look at, this load develops in excess of 2,000 foot pounds of energy. Compare that to the Buffalo Bore .44 load that develops about 1650 foot pounds of energy. I would call that a significant advantage for the .454. Now consider that a cast bullet will generally deliver more velocity than an identical jacketed bullet loaded to the same pressure level. This is due to the reduction in friction of cast bullets compared to jacketed bullets.
My "go to" heavy load for my six inch Freedom Arms is a 340grn cast bullet at 1680fps, as measured by an Oehler 35P chronograph ten feet from the muzzle. This load will take pretty much any critter on the planet, humanely, with proper shot placement. It kills on one end and cripples on the other.
The advantage of the .454 comes from to factors. Pressure and diameter. A larger bore will always drive a given weight bullet to a higher velocity than a smaller bore will if loaded to the same pressure, and fired from the same length barrel. This is because what accelerates the bullet is the force that the pressure creates against the base of the bullet. Force is calculated by multiplying the pressure by the area. Larger area = more force for any given pressure. An additional benefit of this increase in performance is that the larger bore can often offer equal and sometimes better performance with a barrel that is shorter than a smaller bore.
Now consider the operating pressures of the two cartridges. The SAAMI max pressure for the .44 is 36,000psi. For the .454 it is 65,000psi. That is an increase of nearly 90%. Hardly insignificant. Granted, the BB .44 load is loaded beyond SAAMI specs, but how far do you think they are willing to push it? John Linebaugh had several Ruger revolvers pressure tested to destruction and found that they spontaneously disassembled themselves at about 80,000psi. With the ever increasing amount of product liability suits and litigation taking place today, do you really think that BB is loading so far outside of SAAMI specs as to approach the failure point of the very guns that they say their ammo is safe to use in?
None of this is to say that the .44 is a slouch in any way. It is a fine cartridge that will handle most tasks that the average hunter/outdooorsman will ever ask of it. The .454 simply offers a much broader performance envelope. Granted, to truly take advantage of this, handloading is pretty much a requirement, but this is true for almost any cartridge. Measuring the merits of any cartridge by looking only at advertised ballistics from a single ammunition manufacturer, is probably not the best method.
When it comes to power, bigger is gooder in most cases.