Particle effects are more efficient than creating the same effect with Sprite objects, but not by a large margin. Just like with sprites, you should be aware that creating a large number of particles can have a serious performance impact on your game, especially on mobile. Use the ParticleCount expression to monitor how many particles are being created. On desktop systems, more than a couple of hundred particles is likely to impact the framerate. On mobiles, use of the Particles object is not recommended at all since the framerate is usually already limited by the existing sprites in the game; if absolutely necessary, keep particle counts below 50 on mobile for best performance.
To reduce particle counts, try reducing the rate or shortening the timeout. To compensate, you can try making the particle size larger so the effect does not get thinner.