That makes no sense. You can't jump in to live in-race betting when there isn't already a foundation of traditional win betting week to week.
Also for this to work there would have to be full uninterrupted televised coverage. I can just imagine some guy in the United States attempting to wager and NBC breaks away to commercial.
It can be argued that wise guys will find a way to watch but the idea is to expand interest to casual fans and bettors, not merely cater to people who gamble for a living.
BTW, the most interesting in-game wagering I ever saw was on the PGA Tour. There were a handful of British guys who walked the tour every week, following the key groups and communicating with each other. They had their phones open and wagers ready to go with their finger on the screen as the ball was in the air. That's what they were looking for, just the slightest edge that they could pick up in person in comparison to other guys watching the televised coverage. Basically they were rooting for atypical shots, especially poor ones like a ball in the water. They would hit the wager a second or two before it became known to others. I got to know one of the guys fairly well, generally speaking to him at Bay Hill. They probably still do it but I don't see the same group of guys anymore. They were perhaps late 20s at the time. The heyday seemed to be circa 2015 to 2019.