You don't need fast all-out sprint speed to be a great miler, an event that's 80%+ aerobic. Tinman knows that and knows how to make his athletes win these races. Puffer is not gifted with great sprint speed, but is a great athlete with outstanding endurance and aerobic qualities.
Who was better in the 1500/Mile, El Guerrouj or Noah Ngeny, a fast-twitch monster with massive 100m speed and 1:43 800m? Who is currently better in the 1500/Mile, Cheruiyot or Lewandowski?
Ngeny, Lewandowski etc all got this great sprint speed and obviously better 800m times but as long as the race is fast enough, they will not win. Hunter beat Fisher multiple times in Mile races despite Fisher being attested to have faster 100m kick/speed at the end of races and faster 400m times at that time in HS. How? CV training allowed Hunter to start his kick 500-600m out and destroy others with this long, very fast finish.
There is always this complaint about Tinman not doing all-out sprint training in his program (like Magness, Canova, or many other coaches do), but he HAS already stated time and time again that it's not necessary for milers and up, a waste of adaptive energy and unnecessary injury risk. He isn't the only coach with that attitude. Most runners get injured from sprints, and not easy mileage even tho that often gets the blame.
On top of that, and also often stated by Tinman, is that sprint speed is highly genetic and depending on the amount of your fast-twitch muscle fibers. Someone like Bolt got an inherent speed advantage, even without training he would outsprint 99%+ of people even if they dedicate their whole life to maximize their sprint speed.
If you can decide to get Puffer from 13.5 100m dash (FAT) to 13.2 100m dash (FAT), OR to focus on building his stamina and endurance and get his threshold down from 5:00/mile to 4:50/mile, what do you think is gonna make him the better distance runner in the future?
Tinman might say a lot of crap but he is right about how to train distance runners for their specific events, with legit/allowed methods and within their natural range of talent/capabilities.