Yes, there's nothing to loose. They don't even have to make you choose the difficult from menu or something like that. There are a bunch of options, mostly mentioned by Corveone, that could be turned on/off for the players. If those changes were all singular, then the player would have full control over difficulty, even getting a somewhat harder/easier type of playing. For example, one could play with affection on, level cap off, items off, set Battle mode off. That would allow to give different kind of playing experiences and those changes could be reverted at any time.
That said, i found the SV DLC to be quite harder than the usual games. I also like the choice of double battles.