Going to the Lakers for LeBron's last ride is super high-risk, high-reward for a first time NBA coach. If he wins a title, he's a HOF lock and a legend.
If he faceplants, he could be out of the league and take a while to get a second chance, and there's a decent chance of that.
My gut feeling is he's using this as leverage for a contract here and will go to the NBA eventually, but not for at least another handful of years. Remember, Billy Donovan won back to back, was courted by the NBA, even took the Magic job at one point before reneging, and ultimately coached at Florida 8 years after his second title.