We have a separate Resin section, makes sense to have a separate Diecast section.
A lot of people still have that weird bias against diecast models (which I will never understand, BTW)... so it makes sense as far as the forum goes to separate diecasts into their own separate area... if for no other reason than it makes them easier to find, and keeps the "diecasts aren't real models" crowd happy.
As far as diecast models being 'toyish," that all depends on which diecasts you're talking about. Check out Danbury, Exoto or AutoArt, just to name a few... their models are better detailed and more accurate than 90% of us could create with a styrene kit.