Why might safety be more of a concern for a carpenter working on a construction site than for a joiner working in a workshop?

Joiners are required to have safety certifications that jobsite carpenters do not have.
Jobsite carpenters sometimes have to operate dangerous tools while standing on a ladder.
Joiners do not use power tools whereas jobsite carpenters use power tools frequently.
Jobsite carpenters generally work on industrial applications, whereas joiners work on residential jobs.