Board Thread:Naruto Discussions/@comment-25626003-20150728002625/@comment-4646462-20150912000106

Another possible reason the 6 paths' techniques weren't used was that due to Pain's assault on Konoha, the Alliance knows the techniques well and can be capable of countering them. Obito's Juubi seal seemed to be a dimension-type seal, so going intangible could have led to dire results. As for Madara using Kamui, well, given later developments, the Juubi likely saw it beneficial to stay within Madara, and also warping to the pocket dimension is somewhat different than going intangible.