Alternate picking is probably the first picking technique you’ll learn on the guitar. It’s an absolutely essential skill to develop when you’re first learning to pick on the guitar. But as you get better and start playing faster, economy picking becomes a hugely beneficial augmentation of your alternate picking technique.
It’s important to understand the main difference between these two closely related techniques. Alternate picking has you constantly alternating downstrokes and upstrokes no matter how awkward the movements become. Economy picking has you sometimes including multiple downstrokes or upstrokes in a row to minimize the movements your picking hand needs to make.
Many guitar teachers suggest using whichever of these two techniques works best for the piece you’re playing. But there are some teachers that swear by the alternate picking method and will tell you to avoid economy picking. In the end, it’s totally up to you and what works best for you. Try adding some economy picking to your playing and see if it makes certain things you play easier.