Work out the cents per point you would get from any redemption, across airline miles, hotel points and flexible bank currencies, so you can compare them on the same scale.
Cents per point is the cash value of what you booked, minus any taxes and fees you still had to pay, divided by the points you spent, multiplied by one hundred. The subtraction is the step that gets skipped, and it is the one that matters most on international awards where carrier-imposed surcharges can run into the hundreds. A redemption is not free because you paid with points; it is cheaper by exactly the difference between the two numbers.
Every site publishes a table of what each currency is worth, and those numbers are useful for rough comparison and useless for deciding a booking. The spread within a single program is enormous: the same airline mile might return half a cent on one redemption and five cents on another. Use a published valuation to decide which balance to build over years. Use this calculator to decide what to do this afternoon.
For a flexible currency, the guaranteed cash-back or portal rate sets a floor beneath which no redemption should ever fall. If a transfer would return less than simply cashing out, the transfer is a mistake no matter how exciting the destination is. That floor also gives you a clean decision rule: anything meaningfully above it is a good redemption, anything near it is a signal to look harder or just take the cash.
Valuing a first class redemption against a fare you would never pay produces a spectacular number that describes nothing. If the realistic alternative was economy, compare against economy and accept a smaller figure that happens to be true. Points are worth what they save you, not what they let you sample. The award vs cash calculator runs that comparison for a specific booking, and Award Travel Finder will tell you whether the seat is even available before you do the math.