Long throws are great for preparation, but I would not call it a warm up, it doesn't sound like you use it that way, but you neve3r know who is reading, and the importance of a good warm up to prevent injury is important (and stretching is not warming up).
I would say a proper warm up is to increase the distance, once warmed up, the long throws are fine to get ready.
Of course this is just my opinion from my knowledge of physiology and the laws of physics.
Long toss has been in baseball warm ups for as long as I could spell baisballz , although there are exceptions based on beliefs. Remember, the long toss comes after short toss, so the short toss has warmed the muscles. We did this when my brother and I pitched D1 many moons ago, his son's teams D1&D2 still use the long toss before "active" pitching.
Some then run either the 2 or 3 tier station. Some only do long mounds ( 70' fastballs only ) and then 60' fastball and breaking. Some do a 45' short pitch, then 70', then 60'. *** Do not do long mounds with breaking pitches, or at least not in BB.
The Rangers moved beyond the normal 120' long toss in their warm up routines, can't remember just how far back they went, but it dropped their team ERA a good margin without any other warm up changes. Think that was around 2008 or 2009.
Any long toss still needs good solid mechanics, or it's counter productive and can cause injuries. Lots of MLB teams use long toss in between a pitcher's "off" cycle.
^^^^^^ All that said, I have seen medical papers showing both sides. Increased speed and strength in some, decrease in others, some use it as therapy for an injury, some say it caused the injury.