Peter,
The Starwood Amex card yields 1.25 miles for every $ spent if converted to airline miles in most (but not all) programs. When you reach 20,000 Starpoints, that can be converted into 25,000 miles in many of the airline programs (but not all).
I stopped using my United Visa card because $20,000 dollars spent = 20,000 miles.
My Starwood Amex card will allow me to convert 20,000 into 25,000, which is enough for a free domestic ticket.
It's not a sin to convert *points to miles if you aren't going to stay at a Starwood property. I will say that *points are much more valuable than miles; and certainly more redeemable.
As an example, that free airline ticket may be worth 1 or 2 cents a miles under everyday circumstances. Maybe 3 or 4 cents a mile if you need to fly somewhere last minute.
YMMV (your mileage may vary).
On the other hand, if you cash in 20,000 Starpoints in Europe for 2 night stay, you could save $600 plus (3 cents a point). Many would argue a Starpoints is worth as much as 8 cents a point. This is why everyone on the Starwood board hoard their points. European properties are a worthwhile redemption.
Most folks here, including
Inside Flyer magazine, suggest the *wood card.
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