It depends on the manga in my opinion. The split-ups for that manga aren't bad, they give a good cliffhanger vibe and make you look forward to the next chapter.
As you said, the releases would be really slower. Way slower considering not everyone in our group are available every time. So, for now, split chapters are fine.
Chapter 13 won't be a split one anyway btw. And for 14 and further, we'll see and decide