Interesting. I logged into my RR account, and started to change an upcoming trip. It's a $15 increase o/w to go from Anytime to BS. I cannot recall if the $25 BS upgrade at the kiosk covers r/t or o/w. I suspect $25 covers a o/w upgrade only, so I'll use that for my math. If I am wrong, divide the total in half.

While shorter segments on BS fares only yield an additional 0.25 RR credit, the long ones yield an extra 1.0 RR credit. If always taking long flights for 1.0 extra RR credit, it would require spending $400 to attain an additional r/t award. Not great, but potential to break-even on last minute award travel versus buying a last minute rev ticket.

16 award credits / 1 bonus credit per trip = 16 o/w trips
16 x $25 = $400

However, if the BS fare only gives an extra 0.25 credit, it costs $1600 to get the extra award ticket. Insane.

16 award credits / 0.25 credits = 64 o/w trips
64 x $25 = $1600

Unless the motivation is to get CP in less time (which with the above scenarios, we're only at 32 of 100 credits, so multiply $ by 3), I'd just book a rev ticket instead of paying all the upgrades. CP could arguably be worth the spend for some people; but otherwise am I missing something (other than the value of the "free" drink with the BS fare)?