Is GPL License Good?
SCO's Chris Sontag argues there are many reasons that the GNU General Public License is bad for the software industry. The General Public License is not good for the software industry for a variety of reasons.
Conclusion. The GPL and other copyleft licenses are not bad; I just think they're pointless. They have practical problems, and they are tainted by the behaviour of the FSF, but most importantly, I do not believe they have been an effective contributor to software freedom.
It's time to say goodbye to the GPL - Martin Kleppmann
Software under the GPL may be run for all purposes, including commercial purposes and even as a tool for creating proprietary software, such as when using GPL-licensed compilers. Users or companies who distribute GPL-licensed works (e.g. software), may charge a fee for copies or give them free of charge.
GNU General Public License - Wikipedia
What are the advantages of GPL license software?
Advantages for users of GPL v3 software You can use GPL software for commercial purposes. You can modify the software and create derivative work. You can distribute the software and any derivative work you produce, without having to ask for permission or pay anyone.
The GPL License - Flavio Copes
Many consider the GPL a "business-unfriendly" license because of its so-called viral nature: All software derived from GPL-licensed code must in turn be licensed under the GPL. ... If the GPL doesn't work for you, you can purchase the software under an alternative commercial license.
What's so bad about the GPL? | InfoWorld