A surprise, to be sure, but a welcome one.
Personally, seeing the popularity of vanilla i3 and by extension i3-gaps (which some people prefer aesthetically) in conjunction with the combined userbase of debian and all of its offspring, it became apparent i3-gaps should have been available sooner in debian.
If one was to graph the users the users of the debian-family of distributions and every other distribution family out there, it becomes clear that a lot of people might be missing something they are used to using elsewhere (most other big families of distributions have the fork available as can be seen here:
https://repology.org/project/i3-gaps/versions).
And a lot of people have real trouble compiling this piece of software from source (mostly new linux users of the debian-derivatives).
Therefore since i use debian from time to time, when my gentoo box is occupied compiling for 12 hours straight, it occured to me i should package i3-gaps for debian and therefore all its derivatives to give people easy access.
Certainly, a merge is the superior solution and i am glad its actually being considered, but my understanding is that code refactoring/cleaning could take a considerable amount of time, and therefore the package should actually be available as a temporary solution for all those who want to use it, as it currently is everywhere else.
Again, i congratulate Michael and Ingo for their work.