You are right - it works for any level of skill! and I'd like to think of it being reminiscent of what practicas used to be in Argentina - a place where people learn from each other, not from a teacher.
What I found very useful and would like to do more of was to rent a practice room and practice *alone* with a partner, just the two of us. Bring music and work on stuff. You can make as many mistakes as you like. Nobody will care but you two. Costs a bit more than a practica but you can focus more sharply on what needs to get done.