It is generalized that journal publications are normally more complete research papers than those in conference proceedings. However, when applying for a job in the industry, most companies (e.g. Facebook) ask for first-authored publications at peer-reviewed conferences (e.g. ICRA, RSS, IROS, or similar). Why is this? Are these top conferences more valuable than top journals like Nature or Science from an industrial standpoint? Why could this be?
Speaking from the perspective of a roboticist with publications in the conferences you listed and in Science:
Hiring for industry jobs (especially at junior levels) is going to be focused on finding employees who can use and modify existing robotics paradigms to achieve company goals. Conference papers (especially at the venues you name) provide useful evidence of this ability. They are also often the result of a short, focused piece of effort, which matches desired industry workflows on projects.
In contrast, a robotics paper that makes it into Science is likely to either be a description of a high-level principle arrived at through long academic study, or to report a new phenomenon that can be incorporated into future robots, but are not at a tech-readiness level to be incorporated into products or services. Industry interest in these kinds of results is limited mostly to companies that are making senior-level hires and/or are big enough to be running their own research departments.
It depends on what field you are in and the types of jobs you are looking at. In computer science, conferences are typically valued more than journals, although this doesn't necessarily mean the quality of the papers at conferences are better than journals. A popular computer science department ranking site, CSRankings, does their rankings by top conferences, where the three you list are used in the Robotics area.