Is doing a research internship during MSc. studies worth exceeding the standard period of study? Is doing a 3-6 months research internship during MSc. studies worth exceeding the standard period of study?

I am in my 3rd semester for my (course and thesis based) CS MSc. degree. The standard period of study is 4 semesters, but most students exceed it anyway by 1-3 semesters, judging by hearsay.

I have a good relationship with a professor, with whose research group. I will probably have published 2-3 conference papers in a few months.1 The professor would very well recommend me to some peers of theirs such that I could do a 3-6 months "research internship" at another lab in the same field.

Advantages


networking
strengthening my CV - I'd like to keep doing research later anyway, be it in academia or industrial research labs


Disadvantages


I will probably need 7-8 semesters, significantly exceeding 4.
As other labs are very close to ours, I could probably combine internship and thesis work. But my advisor already noted that in gneral time in internship &gt;&gt; time spent on MSc thesis there.
Instead, I could shorten my MSc studies to do a PhD soon afterwards (in Europe you usually need an MSc for starting a PhD)


I don't think the prolonged studies are a problem financially or from the side of the examination office. I much more fear that it could look bad on my CV having necessitated 7-8 instead of 4 semesters.

Does a research internship strengthen my academic CV enough to outweigh the disadvantages caused by overlong Master studies?

1 one paper got already accepted, another two are in progress.
This is a matter of balancing trade-offs and can be viewed in a variety of ways. While I won't go into all of the many ways, here are two ways that taking the internship could be perceived: 

1) You were not able to commit to something you agreed to commit to at the start. Your leaving for a better opportunity may be interpreted by potential PhD supervisors as an inability to stick with a program. 

2) You found an opportunity to build a new network of collaborators, gain new knowledge, experience, and perspective. You will also be making money, which can be used to make your life easier later on. 

There are infinite ways to view the trade-offs, but only you can make that distinction.