Well .org is pretty much the standard TLD for open source projects. While it would be "cool" to use .io it might confuse some people.
It's very common for example that projects have an .org for their Open Source software and .com or other for their business behind it (see wordpress.org vs wordpress.com)
It's very common for example that projects have an .org for their Open Source software and .com or other for their business behind it (see wordpress.org vs wordpress.com)