No US capital gains taxes or IRS filling requirements. More detailed reasons can be found online, but here is one source of more information on why a US citizen wouldn't want to invest in most financial products that aren't US based. https://thunfinancial.com/home/ameri...d-mutual-fund/
I opened an IRA with Schwab from the Hong Kong many moons ago. Often calling them up helps. The main limitation with Schwab if you have a foreign address is that they switch off you ability to buy internationally.