Obito hasn't been using any Rinnegan techniques either, but I do think he can use the Rinnegan. I don't quite remember exactly what episode it was, but I remember Jiraiya saying something along the lines of "He even mastered all of the nature transformations, which is completely unheard of".
From the Naruto wiki:
"This affinity makes it easier to learn how to create and control the nature in question, although even with an affinity this process will usually take any number of years. Shinobi are not limited to the nature they have an affinity to, though. By the time they reach the rank of jōnin, most shinobi have mastered two natures.
Because of the difficulty of mastering a nature and the time required to learn it, it is almost impossible for any one person to master all five natures through natural methods. However, those who possess the Rinnegan or Bashōsen can use all five elements, while Kakuzu got them by stealing other people's hearts. In the anime, Fūka got them by stealing other's chakra. In Naruto Shippūden 3: Inheritors of the Will of Fire, it was stated one who absorbs five kekkei genkai with the Chimera Technique would gain a mastery over all five elements."
I'll try find what chapter/episode this was stated, as Naruto wiki is not always valid.