What is the relation between the EASA Light Aircraft Pilot Licences and the Private/Sailplane/Balloon Pilot Licences?
LAPL (Light Aircraft Pilot License) can be a pathway to a PPL (Privat Pilot License) but can also be just kept by it's own, as it's somewhat cheaper to get and maintain than a PPL.

LAPL has stricter limitations than the PPL, for example they are only valid in EASA countries and not in all ICAO states. Also, LAPL is limited to a maximum take-off weight (MTOW) of 2000kg and does not have the options of upgrading to IFR or similar (Night VFR is an option though) and a maximum of 4 people on board (3 passengers + you).

Therefore: If you are fine with the mentioned limits, you're good to go for an LAPL. If at some point you want to upgrade to PPL, thats not a big issue as it just requires the additional training hours (theory is the same for LAPL and PPL).