Hi there, @Agence_TOUTATIS 
Apologies for the delayed reply!
Glad to say that we already have a request for the booking confirmation. Feel free to upvote it here - Owner can approve or deny bookings after submission.
As for the 2nd suggestion, I completely understand your point and added this idea to the Wishlist on your behalf - Automatically block time slot for all services provided by the same person.
If this idea gets more votes, it might be considered in the future updates 