PRO:
There are two points that make people say that:
- They want bragging rights
- They want to preserve the dev vision of the game, from an artistic point of view (yep, i consider games a form of art, just like movies or music)
The first is somehow lame and could be answered with trophys/achievements only unlocking on hard mode
The second is pretty valid actually, though i don't know if the devs ever spoke about this
CON:
On the other hand, opitions are always a good thing and don't get on the way of who wants to have a challenging experience. This could also help it be more successful from a sales point of view.
I can point to Fire Emblem: Awakening as an example:
The casual mode, that removes perma deaths, most likely was key to the sucess of this title. The classic mode was still there for those who wanted it.
i.e: My sister never played FE and she only begun because of the casual mode, after beating the game she started over on classic, because she loved it.
