It is not clear that the whole office is being covered and it is not clear if it is exclusive use.I mean according to what you laid out:
18 CHF per M^2 per year, CHF 300 per month (3600 CHF per year).
3600 / 18 = 200M^2
So for a price of CHF 300 per month you get a 200M^2 office (according to the website)
The very cheap price indicates it is not and you will have just one seat and you can book the meeting room etc.
Switzerland is very expensive by any standard and you can compare 1:1 with London, Tokyo, Former Hong Kong, Singapore, NY. Even Dubai is quite cheap compared to the Swiss cities which have economic activity like Zurich, Basel, Geneva, Zug etc.I have read a lot of nonsense comments about Switzerland on this forum, after I have been there for a few weeks to sort all my things out, I didn't find anything negative here.
If you come from a third world country or Baltics I believe Swiss is very expensive in the eyes of such people. If you come from a well regulated country (over regulated) with high taxes, Switzerland is cheap.
If you make money and have a good business, want to live in a country which is close to other European countries but is not EU, Swiss is the place. You don't pay high taxes and you don't pay more than what I'm used to for renting an apartment or office.
So from what I have figured out so far when planning to relocate, Switzerland works well for my purpose, I did my math and things are good. I will safe at least 50K euro each year in taxes also while I have to pay for insurances etc.
That being said, it does not mean it never makes sense to relocate there etc. It may very well will and you can save a lot in tax or other expenses and you can still visit clients in europe easily etc, also quality tends to be rather high.