On 90% of the days I would agree, but on busy days, most attractions could use Fastpass - it's not 100% necessary, but they can get use out of it.
Nemo put life back in that pavilion. It wasn't the best possibly addition, but I think it was a huge step in the right direction.
As for Nemo Fastpass, I'll tease our recording this week again. Per Jim Hill, this is very likely related to xPass. At Epcot there are really only 2 attractions that regularly need Fastpass (3 if you don't want to wait 20 minutes for Mission: SPACE). To sell people on xPass they need to create value, whether it's real or artificial. More significantly, The Seas with Nemo and Friends lends itself to customization as part of Next Gen with all of the screens in the attraction. If you think about all of this together it makes some sense - it's really to create perceived value when people are paying for xPass at Epcot.
I really wouldn't be surprised to see Fastpass/xPass queues added to more attractions that don't really need it.