Another reason charm becomes more powerful over time is that the gap between mob HP/DPS and player HP/DPS really widens as you level. At low levels, a charmed pet isn't a massive DPS increase, you (and your group, if you are grouping) have less tools to deal with charm breaks, you have less mana regen and your spells cost more mana relative to your mana pool. See the post above mine for more information on that. At later levels, a charmed pet (especially a hasted DW charmed pet) is an absolute monster, far superior to your animation, you (and other classes) have ways to deal with your charm breaks, etc.
At low levels, your charmed pets won't be significantly better than your summoned pet for tankiness or DPS. But they come with two advantages:
1. For solo play, you can break charm when the mobs are at low health and kill them both for 2 full exp kills, whereas a summoned pet would only net you 1 kill and would take 1/2 the exp if your pet outdamages you.
2. For group play, your charmed pet follows orders. Your summoned pet does not. This was a pretty funny troll by Verant, because your powers of crowd control can get messed up by an unruly pet, and your summoned pet doesn't listen to a thing you say. Also, since they don't listen, you can't make them attack unless you or the pet are hit by a mob.
Playing an enchanter gets pretty chaotic, which is funny since the whole point of the class is reducing the chaos of fighting mobs to make things as streamlined and efficient as possible. You'll be buffing every group member (except bards) with brain buffs and/or haste, crowd controlling with mez and roots, interrupting casters with mez and stuns, slowing every mob... and with charm, you can also do massive DPS and if you aren't grouped with melee, great tanking (mobs at later levels have bonkers hitpoints). The only thing you can't do is heal
[You must be logged in to view images. Log in or Register.] You can also pull due to the calm line of spells, although due to your crowd control it often won't be an issue if someone overpulls (until you start running into magic immune mobs and the like, but those will resist calm anyway)