It isn't going to disrupt anything. They will only review ones where there is a question. The vast majority of 3's are clear, as are fouls from behind the line. They can easily wait for a break in the action to look at a questionable field goal and either add or subtract the point. Unlike football, there are many natural breaks in basketball, like timeouts, where there is already a stoppage in play. Think about it, how many times last year can you remember where you thought a 3 was really a 2 or vice versa or a you thought a foul was committed behind the line or not?
This sounds similar to the protests about baseball using replay for boundary calls, it will slow down the game, etc. But how often do those plays even happen? Has it happened once in the postseason? Since basketball games can come down to a single point many times, in the rare instances this will come into play, it makes sense to get it right.