After reaching the 6th stage of cultivation and learning a mental type technique, of course, Minos would not miss the opportunity to become a painter and musician.
After all, both professions didn't require him to learn specific techniques. Only the mental type technique was necessary. And since he already had this technique for other reasons, it wouldn't harm him to use the full potential of such things!
He had many soldiers with low talents, i.e., people who would take longer to understand their respective techniques than more talented people. But not only that, when using higher quality techniques, such people would take even longer to master than would happen with their previous lower quality techniques.
Because of this, even if these people managed to increase their level until the end of their cultivation stages, it would not mean that they could reach the next stage in a short time!