I like the idea. I'm not a big fan of metagame resources, but having one for very occasional and fundamentally optional use feels about right.
As implemented in 5e it's (generally) too rare for people to use freely. Players write that they have it on their character sheet and then save it forever for that super consequential roll they never remember to use it on. And when they do use it, it's just advantage, which is a bit underwhelming.
The "make it a re-roll" fix helps tremendously with this problem as it is both more powerful, and easier to decide to actually use, as you've already failed and are staring down the consequences of failure. It also makes it a very occasional attempted re-do, which is the level of metagame resource power I can live with and actually appreciate.
For the OneD&D playtest WotC has gone the opposite direction. Rather than making it more powerful and easier to decide to use, they have just made it more prominent and plentiful, with an until long rest cutoff. Perhaps that is better from a balance perspective or whatever, but as someone who, once again, only likes metagame resources as a minor incursion on the game, I don't like it suddenly being thrust to prominence, as something players have to worry about and stress about optimizing the use of on a daily basis. It is also now too prominent to just decide to ignore without actual game balance repercussions. A big swing and a miss from my perspective.