It depends
My last corporate job, 2 of the 3 pilots had A&P rateings. The one I wouldn't trust to fix my dog leash, the other I inherantly trusted my life with. I didn't have my A&P but I held 2 MOS's as a Military Helicopter mechanic so I was functional as a helper. In some flight dept. an A&P can be the difference of getting a job. I would highly recommend against trying to be both a mechanic and a pilot. Some companies that fly overseas or bigger airplanes will dispatch the flight with 2 or 3 pilots and a mechanic. My present company we have a full time mechanic and he earns his pay. One of the biggest responsabilities of a mechanic is tracking scheduled mainitenance, ordering parts, and forcasting time to put the airplane down, as well as reacting to non scheduled maintenance. That occurs when a flight is ready to leave and the pilots discover something aint working right. Do you want to get greasy or sweaty while wearing a shirt and tie ... I wouldn't
The biggest thing I see with Pilot / Mechanics is when the airplane is at home station between flights, that is my time to go home and get caught up on chores and family responsabilities. For the Pilot / Mechanic its a time to go to the hangar and work on the airplane, order parts or schedule phase maintenance. Its a big tax on your "free" time.