You are already in a position where you are paying extremely low trading costs, so I would likely stick with that for the bulk of your trading and investing given your needs. (writeyourownreality.com)
There is also less turnover in ETFs than in most actively managed funds, resulting in lower trading costs and fewer taxable events, such as capital gains distributions. (indexologyblog.com)
Being a reserve currency lowers trading costs, lends prestige. (alephblog.com)