Yep - you nailed it.
@Jesper85 - think of it this way - because following a joseki sequence allows both participants to get something out of the interaction, the other person might complete their half of the sequence because it allows them to keep the smaller portion of that corner, or trade giving you early corner territory in exchange for greater influence they can use in midgame
It also saves you the work of reading out each possible move / re-inventing the wheel every time you play an opening, and the comfort of knowing you’re not going to make a lethal reading blunder, and suddenly lose half of that corner
Lastly, as Gia mentioned above - knowing when a joseki sequence is complete will either let you know your stones are settled, and that you can be fairly confident of retaining your portion of that corner - OR - you can know when it’s almost settled, and play an extra sente move somewhere else - which is very valuable in the opening
This 19x19 FOR BEGINNERS article will hopefully dispel some of the mysteries around joseki
good luck