Whats the purpose of Dated Gear?

I use to play FFXIV 1.0 a lot when it first launched and then had to quit about 7 months in.

Now that I'm back, I don't really understand the point of Dated Gear? Almost my entire inventory was listed as Dated and the rest of my gear I couldn't wear anymore due to the lvl change.

I keep trying to search for more info on these items but the only thing I can find is that they just can't have materia attached?

Is there any point of keeping these items? Is there a way to trade them in for their replacement? Any benefit for keeping them?

You can craft them into better gear.

its original v1 gear - for whatever reason, there were changes to v1 that made old gear 'dated' and introduced adjusted versions

i believe you can still convert them to materia - not sure though, havent tried yet in v2

Spiritbond them to 100% then convert to materia.

They are there just if you like how they look. When they revamped gear in 1.0 some classes became unable to wear gear they could previously, so this was kind of a compromise.