This is what I understood from this FAQ question:
What criteria are used to select the data supplied by swisstopo free of charge?
The data offered free of charge is that which can be acquired online independently or automatically by users via the Internet and which therefore does not require any effort on the part of swisstopo (= standard digital products). During the first step, the most popular standard digital products are available for online acquisition. In future, however, the service could be expanded to include other federal geodata that are the responsibility of swisstopo.
(as maintaining the swisstopo portail is an effort).
However after further reading it seems that the map server will be available free of charge too, so this is very good!
What does “free of charge” mean exactly? Are there any additional processing fees?
Free means without costs or fees for the standard digital products. These can be downloaded free of charge from the Internet by users without additional processing.
For geodata:
Free of charge means that no fee is charged for the use of the data. It is also free if the user downloads the data from the Internet him or herself. However, if the data must be prepared and sent by a swisstopo employee, a fee is charged for the preparation of the data. From 1 March 2021 onwards, not all swisstopo geodata will be available for self-download. The number of datasets will be gradually expanded.
For geoservices:
swisstopo geodata are integrated into the various geoservices of the Federal Geoinformation Infrastructure. These services can be used free of charge and without registration. For the use of service-based data via the geoservices, a maximum number of requests per time unit is set as a usage limit. Within this limit, the use of the data services is free of charge. The usage limit is to be observed as far as possible ("fair use").
If the specified number of requests per time unit is repeatedly exceeded, swisstopo may conclude a contract with the data user for a higher number of requests. This use is then subject to a charge.
