It's not that just Chewbacca automatically picks up spice tokens it us that an elite figure automatically gains 1 success on any attribute test it performs. That goes for any mission in which an elite ally is available to perform an attribute test.
The main reason I worded it that way is, if I remember correctly, the mission says that Chewbacca automatically picks up spice tokens with an action and doesn't need to make an attribute test.
I'll have to double check when I get home but I do believe it is just that Chewbacca can action to test which due to the auto sucess equates to Chewbacca picking up the spice token as an action. It would seem pointless for FFG to give him that specific ability when he has it per the overall rules. But again I'm only somewhat sure on that.