To improve rhythmic independence? Of course. But also:
- it might lead you to use different voicings than the ones you usually use for comping. Sometimes a voicing might be too low and sound muddy when played with the left hand in the lower part of the keyboard, but the same voicing played higher up will sound OK due to the absence of low interval limit restrictions;
- the left hand is generally weaker and slower than the right hand. Such technical restriction forces you to rely more on musicality, inner hearing and singing when improvising with the left hand. When you then go back to improvising with the right hand, it feels a lot easier! Musicality is now right at your fingertips, with the greater technical ability of your strong hand available to serve it.