It is neat that DMs can simply alter stats to how they choose. I recall an anecdote from a campaign I was in wherein our fighter decided to duel a warlock. The duel started and the warlock quickly showed that he was pact of the blade, but he also kept using spells. One of the players at our table continuously tried to figure out his warlock level/ if he was multiclassed when the DM finally stated to him that the warlock, “is a statblock. He made a deal with a patron but does not necessarily follow player rules.” While our fighter lost the duel, the experience was eye-opening for that other player. The inclusion of trapping spells that ensnare and annoy are also great for combat from the DM’s side of things as it can be annoying to be hit with Magic Missile and take automatic damage (or even succeed on a save to still take half a fireball). Of course, these are still part of a combat wizard’s arsenal and she/he should pull them out in a fight, but getting plinked for average 28 damage a turn (14 on a save) can be annoying when it’s every turn.