LOIs are beneficial to both the buyer and seller. The fundamental goal of the LOI is to confirm that a 'meeting of the minds' has been reached prior to both parties making the large investments of time, energy, and expense required to execute a Definitive Purchase Agreement (DPA), aka Asset Purchase Agreement (APA).
Even taken at their word, it doesn't change the fact that they are using documentary procedures that are unusual, and abnormal. Contact any business college, or speak to established traders or people working for large multinational corporations. Talk directly to international bankers on this.