It makes no sense (in serious games and tournaments) because computer analysis quickly reveals the use of third-party programs. Strange as it may seem, the player's chess behavior is very easy to predict, and if he "suddenly" starts to play better than his level, this immediately attracts attention.
But what if the player uses third-party programs from the very beginning? Then the computer will not be able to notice the change in the player's behavior and determine that his level of play has changed. The computer will perceive this as normal chess player behavior.
In addition, if a player plays games as first lines of chess engines, then he automatically receives a ban on almost all chess sites.
This surprises me a little. Chess engine programs are written by people and loaded into it with standard moves, combinations, debuts, that is, everything that was used or is used by chess players. Any average chess player can use one of these options, but this does not mean that he is a cheater and there is no reason to ban him.