I don't see it as a "drawback." I see it as an additional option so I can decide how I want to use the energy available to me. The left display allows me to monitor how much battery energy is going into the environmental systems, etc. But, I've only had it a month so I'm still learning...
I do love the EV only mode...smooth, quiet, never have to go to gas stations AND my electric bill came yesterday so I know for a fact it's very economical!