I think they shouldn't add any.
Many games with playable races end up:
1: race becomes just a glorified secondary classes (a human fighter does not play like a dwarf fighter)
2: every member of said race (that's unimportant to the story) is flat and stereotypical (elves are haughty and know-it-all, while dwarves are hardworking but brash)
3: Humans often are the least loved/respected among the playable race, storywise
If the team feels confident that it will add more to the game, then go ahead. But if they add it simply because it's fantasy, well the game might end up with a generic feel to it.
If they add races just because it's a fantasy setting (so let's add them) then yes, don't even bother.
However, if there is a solid story, mythos surrounding the races as a whole and they offer to the lore/gamplay individually with different stats, abilities, gameplay mechanics... Etc. Absolutely, bring them.
Generic race additions though? Is a sin. Leave them out if there is no true value to them. (I doubt Playdek would shoot themselves in the foot by doing this) still I had to say it.
Bring them if they can bring life to the atmosphere the way Skyrim's different races do.
Honestly, Fantasy races feel a little cliche at this point. I would prefer it to be humans only, where the main differentiators are social, not physical. Things like class, nationality, and religion seem to be much more interesting than differences in physicality.
^This makes just as much sense and adds a good rebuttal to this threads topic.