I agree with you about there being a running pace that is too slow and that feels like plodding. Personally, I view very slow running speeds as merely transitional acceleration and deceleration velocities. I would see a Galloway style run / walk regime as being more “natural” for those who cannot maintain a faster pace, then some “forced” slow continuous shuffle / plod.
There have been several studies which have tried to examine various running paces and injury potential. In my opinion the one below came up with the best conclusion, in terms of running and longer distances. It concluded that there is a “sweet spot” of running speed, around 11.1kph, not too fast, but not a plod either ( for most), where the peak impact forces of each stride are not too high, but there are also less chronic forces from too many steps per distance ran. The study concludes that an interval (run / walk approach) might be best for those that could not maintain this pace continuously.
Another study examining the same thing concluded that faster running speeds were better than slower ones because you took less steps per distance ran. This didn’t make sense to me, as it completely ignored peak impact forces. For example, you will cause far more damage to a surface if you hit it once with a hammer, with a thousand pounds of force, than you will if you hit it a thousand times, with only one pound of force.
This is a possible issue with sprinting, especially for the older trainee. The peak forces per stride ( or with plyos…especially if too ambitious) are far greater than with slow running / jogging. To answer the OP’s question…this is why so many probably shy away from it. The injury risk is real. As my right knee testifies, a chain is only as strong as it’s weakest link. And you don’t know how strong that link is, until it breaks. As fisky has rightly said, as older trainees, we recover from injuries and / or harder efforts, much slower than our youthful selves / counterparts. Sometimes also, our brains, flooded with memories of what we used to be able to do, fail to listen to what our current bodies are telling us. IF we are to incorporate such faster training into a weekly regime, I think it is prudent to err on the side of extreme caution, in terms of volume, frequency and probably especially intensity, and do a lot less than we think we are capable of. Always keep a tight hold of those reigns, especially if you are doing this for no competitive aspirations. No one gets faster laid up on the couch.