I haven't looked at it in detail but I expect:
(i) that the paperwork can be burdensome (as already mentioned);
(ii) if you charge VAT, you can also recoup VAT that you have paid on services/goods you have purchased. Accordingly, the actual "cost" or price increase of charging VAT depends heavily on how much services/goods you purchase in order to provide your own services.
(iii) similarly how any "cost" or price increase of charging VAT affects your own customers is dependent on whether they are end consumers or they themselves charge VAT (because in the latter case they can again recoup such costs).
This website lists when a voluntary VAT registration could make sense:
https://www.kmu.admin.ch/kmu/en/home...taxes/vat.html
However, you would probably need to do a specific analysis whether it actually make sense. Let me know if you need the contact details of a VAT specialist.