From BKK, L888 is a shorter route to Europe than going south through the ME. But it has significant challenges. First there is the very high terrain. Safety heights are above 20,000 ft for lengthy periods. In the event of a depressurisation, you need to have sufficient O2. A 15 minute chemical O2 generator is not going to be enough. Escape procedures to cover a depressurisation or engine failure are complex and will most likely require special crew training. If you have got all those operational & technical details sorted, the final challenge will be obtain Chinese approval to fly the route. So unless an airline has already configured their aircraft, trained their crews and obtained Chinese approval to fly L888, it’s not going to happen (quickly).