Erza Scarlet

So I was doing cross server dungeon on EU and I happened to find out that even low levels can sign up for Tomb of Exile, which only drops like lvl36+ items. Now I do not want to exclude people from entering, but please what does a lvl21 blademaster gain from tomb of exile? It will only slow down the party dps. This is also for other dungeons of course but Tomb of Exile is an example. What does the community think of this matter? should there be a minimum level requirement for dungeons or just leave it as it is?