Libraries have been involved in participatory learning for a long time - think about visiting authors that allow you to ask questions about how they write, computer classes where you sit at a computer and apply what is being taught, book clubs where folks share responsibility for the discussions, and reference sessions where librarians teach people how to find information on their own. The Makerspace is an extension of this as well as the fairly traditional role of the library as a community space. In a Makerspace, knowledge and skills are shared democratically across age groups. The library serves as physical resource, materials resource, as moderator, and perhaps also as teacher.
Having said that, it is not a match for every library's mission, and it also dilutes a library's focus. We do so much already, and to keep adding things on our plates means we probably do all things less well. For some libraries, it may be an attempt to be more relevant to an otherwise disinterested community - like gaming, which was about getting kids into the library where they might discover the other cool things we do, and making the library a place were kids feel comfortable coming so that they might come back for other reasons in the future.
I personally think it's a trend, and like gaming, it will be attempted and then replaced in many libraries, surviving in the few where the community really takes an interest. I think in the library world, we have a tendency to jump on to new ideas because other libraries are doing them instead of really looking at what our community is asking for. I don't think it is a match for my community any more than gaming was.
I do see a need in my community for community engagement, however. People come into the library to connect with other people - the staff, the volunteers, the other people in our various programs. They come into the library to learn, and they enjoy being introduced to new subjects and ideas. I don't think the idea of a Makerspace is outside of our mission, I just don't think it is a fit for this particular community.
PLA has a webinar that might be of interest here.
There is an interesting defense of makerspaces here as something a community needs (but not necessarily attached to a library).