My experience is that many landlords are fine with this. The trouble is that it takes more time that setting up a rental deposit account at the bank. But the tenant does not have to come up with a lot of cash that will earn practically no interest.

One thing to note: if you have not been issued a B permit yet, Swisscaution will ask for a copy of your employment contract.

Also, once everything is approved, the guarantee certificate is issued to the landord and the tenant. It is sent by A post to the landlord but B post to the tenant. Talk about being cheap!