This statement talks about people who tend to take temporary jobs so that they have more time to do other things. I believe that it has some disadvantages but definitely the advantages outweigh the negative sides of having temporary jobs.
On one hand, people believe that one can get plenty of time to work on new skills and build something innovative and useful which can be beneficial in shaping their career while having non permanent jobs. People can also explore new fields and pursue other things which attract their attention while having a side income from their part time employment. For instance there is a famous cosmetic brand name Sugar whose owner was offered a competitive salary from a reputed company to work as a full time employee but instead of taking permanent a job she took a temporary job with 10000 rs stipend and continued to follow her passion by investing her time to build something big rather than spending time in job and as a result became a very successful businesswoman.
On the other hand, there are few disadvantages of having temporary jobs such as, a feeling of uncertainty towards career and having constant mental pressure to do better can sometimes lead a person to take wrong decisions which can affect their goals. For example, a friend of mine quit his permanent job and switched to a contract based employment to make his swimming skills better but was not sure about building career as a swimmer and at the end he lost the full time job and was also unable to perform well in swimming due to the constant pressure.
In conclusion, I believe that with clear mindset and having proper plan of actions, one can use the extra time to build a very strong career in their own field which overweights the disadvantages of doing self doubt about their future goals while not having permanent job.