Because you can have up to 25 different accounts for free, it's easy to keep your money in different buckets but still manage each account in one spot. (thesimpledollar.com)
You will get the things you want * years * sooner this way than you will by splitting up your savings into different buckets for each goal. (getrichslowly.org)
It does indeed appear complicated but just think of it as different buckets of cash store in the same vault. (money.stackexchange.com)