For one thing, all points are not created equal.

With my Starwood AMEX, I get 1 starwood point/$ spend, because I don't stay at Starwood properties. I have no idea about the points/$ for Starwood spend.

Buf I'm averaging about 5.5 points/$ with my Hilton AMEX. Consequently, I can rack up around 100K/year without ever setting foot inside a Hilton property.

Beyond that, the points required for a cheap Hilton property is usually not worth it. Other than an Opportunity Level award a couple of years ago, my points go for top end stays at Paris, Rome, Budapest, etc., where I really think I'm getting value for the points.