I think in polyamory this can be a successful relationship structure. For the exact reason Ygirl said.
Having only been in two long distance relationships before, one purely monogamous, the other was up in the air, one was a failure, the other, I ended up moving out west and marrying her
. For the failure It was an age thing and the distance was about a 24 hour bus ride. In the end it just didn't work. I think even at 16 I asked if we could have an open relationship so I could fulfill any physical requirements a 16 year old boy may have had. Great conversation when you are that young.
All that said, my perspective in how I view things has changed and is always changing and being challenged. I think it has the possibility to be a smashing success depending on the people involved.