A good higher difficulty: Enemies have more and new moves, more aggressive, new mechanics that changes the gameplay while offering more challenging, less resources making you manage your items carefully. The game still relies on your skill.

Artificial Difficulty: Bloated HP, bloated attack damage which makes the fight just tedious because you fight the same enemy (especially common in mobile rpg games where you need to buy boosters to progress faster through this walls or suffer a month of grind). Fuck skill, we will bring you down using one shot attacks with 0.5 sec windup and invisible traps and holes in the area. Oh you didn't do Siegward's quest which is easily missable in the game? Have fun suffering through Yhorm bitch.

Most games have artificial difficulty, but as long as the tuning is not over the top that you have to resort to cheesing, microtransaction and hidden shit then it is fine.