I'm looking at Vanguard 500 Index fund. There are three different options.
Admiral share (VFIAX) for people who has $10,000+, and the expense ratio is 0.05%.
Investor share (VFINX) with minimal investment of $3,000, and the expense ratio is 0.17%.
Finally, ETF version (VOO), which does not seem to have minimum purchase requirements, but still have low expense ratio of 0.05%.
My question is based on the expense ratio and minimal fund required, ETF seems the best. Are there circumstances people will choose top two options?