Yes, that is the compelling reason to go now rather than later, even though the World Heritage Site designation will soften the impact of increased tourism. LP is a special place and, in my opinion, more interesting than Chiang Mai or Phuket.

If you do go, take crisp, new bills (U.S. dollars preferred). Lao merchants are particularly persnickety about the condition of paper money, often refusing to take bills that aren't pristine.