I was discussing this topic with a colleague and am interested in some other opinions. He was proposing using the GetParameter service to get the robot description from the robot_state_publisher node. I was suggesting we subscribe to /robot_description. We are working in a single-robot environment.
What do you prefer and why?
The way I see it, writing the service call makes the code using the robot description clearer, as you see it’s only received once, and waiting for the response is clear. In contrast, the topic subscribing code looks like you might be receiving it periodically.
On the other hand, you how have to specify the node and parameter name, so if for some reason RSP isn’t there or doesn’t have the robot_description param, and instead some other node is publishing it, it won’t work. But to be honest I’ve never had this be the case in any ros2 systems I’ve worked with.
Maybe it would be the best of both worlds if the robot_state_publisher had a /get_robot_description service? Or maybe rclpy needs some built-in helpers for making getting the robot description, or in general latched topics, cleaner? Or maybe these things already exist and I am unaware 
Looking forward to hearing from others on this topic!