It's probably just me, but there's something nostalgic about not putting spaces in Pokémon's nicknames. Some examples include my Florges named BriarLeaf and my Buzzwole named TerryCrews. It reminds me of trying to squish your funny nicknames into the 10 letters. Even on Pokémon Showdown (where you can give your Pokémon long nicknames) I will still do this (another example being my Clefable named PixieQueen, not Pixie Queen.)