Cross Training in Positions
Just a little bit ago I spoke of cross training on another instrument to help you with your musicianship... only if you have "extra" practice time, remember?
Positions can be thought of in the same way. I generally like to spend the first three years with a student in 2nd Position. This gives them a "first language" from which to improvise and can be expanded upon and used to help understand how other positions work down the road.
If you do have "extra" practice time, spending time in other positions will not hurt you in any way... you won't get confused when playing in 2nd in other words. It takes a long time for improvising to happen, and learning two or three songs in a given position will not mess your 2nd Position playing up. What it will help you with is to move you across the range of the instrument more (3rd Position uses a lot of the high end... 1st Position uses a lot of the high and low end); help your technique (1st Position requires a lot of bending control on the high blow notes and the 3 draw on the low end... 3rd Position uses a tremendous about of bending control on the lower three holes); and to intuitively get more out of your IV and V Chords in 2nd Position (the IV Chord is like playing in 1st Position and the V Chord is like playing in 3rd Position).
So... if you have "extra time," dig in and have fun!