Thompsons were massively popular in China and Russia in the pre-WW2, WW2 and post-WW2 era, being sent as lend lease in the case of the USSR and Nationalist China as well as sold commercially to various Nationalist factions. They were big, heavy, fired a big cartridge, and generally of finer manufacture than any domestic submachineguns. They were also rare and foreign, which almost always adds allure.