Board Thread:Theories and Speculation/@comment-34656247-20191119070420/@comment-9782468-20191121010543

The point is, all the group had to worry about getting warped by Obito. Which shouldn't even be an issue if they're much faster. Kakashi has reason to worry because he's probably the slowest of the group, but the Sharingan helps.

Bee has Tailed Beast power amping him

Naruto with KCM is physically the fastest living being most likely at that point

Guy is also no slouch in speed.

And they all had to fight him simultaneously to still not land any real hits on him.

In fact, Obito was able to sync his movements with Guy's well enough to catch Guy's nunchuks, which have to have been swung really fast.

Obito using Kamui isn't a speed feat, but his use of counters is considering he can still keep pace and keep them on their toes, despite all of them having some notable feats in speed, especially Naruto.

EDIT: Also @Jason, Obito used Kamui to avois Amaterasu's damage. Obito noted that if he hadn't kept his abilities hidden from Itachi, he might have died to Itachi's trap. Itachi obviously already knew about Izanagi, but what he didn't know about was Kamui's mechanics.