Why wouldn't they have thought of that?
Our hero who shall now be named as Bob, in 55% LMC armor ventures out into the world looking for treasure. Bob finds a deadly, cross-eyed bird foaming at the mouth - also known as a harpy. Bob spends all of his mana trying to kill the beast but alas, it still has 10% health left. Our clever hero, Bob, thought if he were to take off all his armor he could regain his mana quicker. Quickly he runs about 50 tiles away and takes off all his armor and waits for his mana to be replenished. His mana gets replenished and he puts his armor back on. Bob runs back to the beast from hell and 'Corp Por', 'Corp Por'..... it's dead...
Let's discuss Bob's decisions and how it would differ if he could throw off all his gear instantly. It took him all of 10 seconds to take his armor off (Bob had a lot of practice at this.) If Bob was able to do it instantly he would have saved himself 10 seconds, but he still had to then wait to regain his mana. Meanwhile someone else in 45% LMC armor was able to continuously cast spells, and kill the beast before Bob.
My point is that a player with 55% LMC that switches to a medable suit has the penalty of doing nothing to regain all his mana back. A player with 45% LMC isn't having to stop to regain mana because it is regaining while he casts the entire time. The difference insta-suit switching saves a person a small amount of time. However, insta-suit switching doesn't enable a player to do this, the player is more than capable of taking off and putting on armor without doing it instantly. In this case, it just saves time.