It's a relic of an era long past. Not worthless, IMHO, even if it does nothing for you.

Pre-CU, I believe these holocrons gave instructions that guided a force-sensitive being along the path to becoming a Jedi.

Post-CU/pre-NGE, A holocron (light or Sith) could fill a Jedi's depleted force bar in an instant. This was invaluable to a Jedi that was attacked by a BH while grinding, or for some other reason in combat and having a less than full force bar. All Jedi powers (including lightsaber combat) used force energy. A Jedi who found himself/herself suddenly forced to defend against a BH, would be unable to prevent his/her own destruction if reserves of force energy were depleted. Having a holocron ready in one's inventory (and on a hot-key) could refill the force and allow that Jedi to defend himself/herself (or use the force to escape).