Compared to the other methods, this one involved the least expense, the least waste of time, and the smallest risk!
After all, the merchandise from the Fictional Church was designed to be affordable and user-friendly; they didn't have especially expensive products. The downside was that once the summoned beasts quickly grew stronger, they might start to look down on their trainers and then abandon them, demanding that the trainer become stronger before commanding them again.
The fifth training method was to "draw attribute tags".
Not only could the summoned beasts draw them, but the summoners could as well. If the summoned beast didn't draw any good attributes, but the summoner did, switching their statuses might also be possible. After all, as long as it fit the condition of one doing the summoning and the other fighting, it was all good!