Eh. If the Dalish gods turn out to be dicks... well, that's that. It doesn't change the fact that elven culture is just as valuable as Andrastian culture, and it doesn't change the meaning of the quest for knowledge. Sera's right in that way: it's better to look ahead.
The quest for knowledge shouldn't be shrouded in mysticism and ritual all of which is gatekeeped by alien beings that demand vainglorious worship for anyone to obtain such knowledge. I mean seriously, did I really have to do that stupid prayer to Mythal to get my pet dragon? Oh well. You're right though, the quest for knowledge is important especially in regards to looking ahead for a better future. Sera should be able to see that and get over her prejudice and fears.
Really, I think Sera's problem with all the Dalish magic/religion stuff is that all the useful wisdom in it is wrapped up around a bunch of scary mysticism and weirdness. Now if Dagna explained it all scientifically using alchemy and runes, stuff that non-mages can use, then maybe she wouldn't be so terrified.
She is a Tempest after all, and is totally fine with semi-magically substances that aren't danger to anyone but the user and can't possibly summon demons.