that's the way they were designed to be used
Whenever I see this, I am caught between a cringe and a chuckle.
There are very few handgun designers alive today, feel free to ask them how they designed their guns to be operated. The designers of the DA revolver are not in that group, however, and I have yet to find any verifiable instructions from them on how they intended their guns to operated.
As far as I'm concerned, the only DA revolvers designed to be used DA (exclusively) are the ones with internal hammers. If the DA gun has a hammer that can be manually cocked, then clearly the gun is designed to be capable of being operated either way.
Generations of shooters were taught, and believed that the DA feature was a "point blank, emergency use only" feature. Comforting to have, certainly, but not a practical thing for general use.
Today, we realize that is not the case, and many, many shooters have proven DA can be mastered and used quite well at beyond belly to belly distances.
HOWEVER, there are still a lot of us who's use, and opinions, hold to the earlier practice.
99.9% of my shooting is SA. My life does not include any regular possibility of having to hold someone at gunpoint, or be involved in a gunfight. I don't play shooting games where speed is a factor, because compared to me, snails are pretty quick and turtles are blazingly fast.
I am, however pretty accurate, and that has always been enough for me.
I'm totally fine with any way YOU want to shoot YOUR gun. But please, don't beat me with the fact that I am going to DIE because I don't extensively practice DA shooting. (yes, I have actually met some people foolish enough to claim that).
#1) it hasn't happened yet, and since it hasn't happened in the past half century, I doubt the next half century will be significantly different in this regard, if I am so lucky as to live that long. And #2, I am confident that at the point blank range I would choose to shoot DA if forced, I would be accurate enough. (this might not prove true, but until reality shows me it IS untrue, I shall continue in my blissful ignorance.
)
I'm a recreational shooter, not a LEO, or a competitor, so my wants and needs are not the same as theirs, or probably yours.