In the context of basic income it means such a populist policy would be have different political barriers.
Just for the record, that's not as wonderful as it may seem at a first look. Direct democracy has shown its limits some times during the last year. The fundamental issues being that you can only vote yes or no for a fixed text, while a law is usually supposed to be discussed in a parliament in every detail until an agreement can be found.
1. An addition to the constitution. The parlament then has to implement that into law.
2. A referendum on a law that has been passed by parlament. This allows the citizens to revert a parlamentary decision.
There is no way to vote on a new law directly. However you can get close by just having a very detailed constitutional change that doesn't leave a lot of options for implementation open.