I only used to spam during the first few rounds of beta 2. Then I realized what the system was really about and never had to spam again.

You should learn the animations associated with each of your skills. Some have longer animations, some shorter. When your character is still finishing its animation, you cannot activate a new skill (which will activate a new animation). However, the game already have a built-in skill queuing function that will let you press your skills a little early.

These are not "instant" abilities as in "instantly take effect the moment I push it". These are just "off the GCD". Next time watch the animation, and you will become proficient at knowing when to push what buttons.

Don't chose to spam the buttons because you refuse to learn the system. Let's learn the system and play it the way it's supposed to be played!