I had this position with Black to play 1-1.
I've played 10/7 8/7 , making the 7 point and trying to keep the white checker blocked. But according to the bot, it is a blunder, and the 3 top moves involve hitting with 3/2*(2). I don't get why it is better to shift 2 checkers on the 2nd point, where they won't ever play again although we are still at the beginning of the game and black reenters very quickly on a 3 slot board. Any idea?

Usually Prime two checkers, hit one checker.

Black likes to exploit the very weak homeboard of white. He has to commit himself to a blitz strategy, and being hit is very likely to help him.

Switching points is a routine play in a lot of middle game positions. To see why, let's compare a play like 8/6 3/2*(2) to your first choice, 10/7 8/7.

If you switch, there's a huge upside when White dances. Look what happens if White's next roll is 11 or 22 or 66. Those are very strong if White gets to play them, but worthless if he's on the bar.

There's no real downside to switching, even when White enters right away. The 2-point is not ideal, but neither was the 3-point. The rolls that enter and hit one of your blots are not strong for White because of the blots in his board. In short, big upside when he dances, no real downside when he enters.

Making the 7-point, on the other hand, doesn't really do much. White is 8 pips ahead in the race and can keep moving and building his board. It's going to be hard for you to make a prime with two checkers already on your 1-point.

The rule quoted above about priming two checkers and attacking one checker is a useful one. Here's a position that's a pretty ideal application of the principle.

Thanks! I didn't know about this rule of thumb.