It used to be you could buy fractions of a mutual fund, but not ETFs. Recently, brokerages have started allowed you to do fractional ETFs as well though.

There are some minor advantages to funds left, especially in taxable. Some of the funds do their best to allocate certain costs to the ETFs so that ends up more favorable tax-wise.

The real main advantage of funds vs ETFs is they don't bounce around in price every millisecond.

One benefit to Mutual Funds is that you can do things like reinvest dividends, or investment plans. It's not a fundamental advantage that a mutual fund has, but no brokers that I am aware of would let you do those things with an ETF. So if you have long term "forget it" account, with ETFs it will accumulate cash from dividends. And the tax benefit of ETFs doesn't really help in a tax advantaged account (e.g. retirement). Finally, theoretically at least, when you buy an ETF there is an explicit "transaction cost". Even when they don't charge you a commission, there's a bid ask spread. Mutual funds trade at NAV both ways (unless of course there's an external transaction cost separately disclosed).