63244727_SoftwareSwirl__Incremental_merge
[0] Testability, fixability [Direct merge] The results of a direct merge cannot be tested until the whole merge is done. If you mess up one part of the merge, there is no easy way to revert only that part. [Rebase] The individual rebased commits can be tested. But if there is a failure, it is nontrivial to figure out which of the changes on master interacted badly with the rebased commit. [Incremental merge] 
Each pairwise merge can be tested individually. If one fails testing, it can be discarded and redone without having to discard earlier pairwise merges. If a failure is discovered after the incremental merge is done, it is possible to use git bisect to find out exactly which of the pairwise merges was faulty.
SoftwareSwirl
Incremental merge