Cleanliness is a trade off between burn rate and temperature. Many combustion systems are very inefficient, heck, you can see that in modern engines. To raise fuel efficiency, one of the things they did as raise engine temperatures, modern cars reach temperature fast, run hot, and if you have a coolant leak, the engine seizes fast. To achieve “cleanliness” in a powder, that is, less powder residue, manufacturers have to provide a fast burn rate and high temperatures. Titegroup is a “clean” powder but there is little spread between minimum and maximum charges, and it is peaky. Small changes in case capacity, maybe the measure dumped a little more powder than you needed, and it does not take much to spike the pressure curve on a fast burning powder. It also runs hot. I was handed a Glock that had been rapid fired with Titegroup and the slide was too hot to touch.
It used to be that Bullseye was the fasting burning powder on the market and you would hear all sorts of blow up stories with Bullseye. Faster burning powders do not give you much margin of error, and the current craze of “clean” burning powders have reduced that margin even more.
I have shot kegs of W231 in the 45ACP, it works exceptionally well in the things I want: accuracy and function. Why change? Bullseye is outstanding in the 45, it is the original 45 ACP powder used in the 1910 cartridges fired in the test and development of the 45 service pistols. Bullseye has given excellent results in M1911's and M1928 Thompsons in ever war it was issued.