Should the Heavensward Leveling dungeons and trials have item level requirements?

[Miste]

The Level 1 accessoires you get at the start with a new character can be used till 30 with no problem and tanks can use them even till 40.

Please tell me why it makes sense to do that though when there are NPCs in each city that sell accessories for each role type up to level 29 that cost minuscule amounts of gil to buy?