I think if you're going flat out for a high MGP car it would be worthwhile. In my case I really like the reliability of a large battery.
I kinda hate to admit it but my beast weighs about 3000 lb PLUS my tools that ride in the wagon cargo area. Weight is part of the deal with this vehicle. So saving maybe 20-30 lb with a smaller battery doesn't seem to be my path. Before I got interested in FE I searched out the largest batteries I could jam in there. I want to be able to start always, and I also like being able to jump start other cars as a favor.
My commutes have been about an hour each way for several years so I'm glad to have the tools along. She has over 312K miles on the clock and in the eight years since I threw the tools in the car I've used them during the commute four times so far, plus one flat tire change.
Currently getting +/- 50 mpg in fall weather. EPA is 31/39 so not too shabby. WAI, fuel cutoff switch, full belly pan, smooth wheel covers.
Now driving '97 Civic HX; tires ~ 50 psi. '89 Volvo 240 = semi-retired.