What’s the difference between VFINX and SWPPX?

Vanguard VFINX asks for a $3,000 minimum investment with a 0.04% expense ratio, while Charles Schwab SWPPX asks for a $1 minimum with a 0.02% expense ratio. What am I missing here?

I literally see no difference other than the price. Please enlighten me, cause I don't get it.