Are JSA sanctions designed to change your behaviour,to inject urgency into your job-search?

Kind of...although how effective it is questionable! JC+ PAs are sanctioned themselves for not putting enough customers under sanction so the stick is being used for staff & public so don't take it personally, if you're unfortunate enough to be unemployed long enough regardless of how motivated or effective your job search you'll likely find yourself under sanction at some point...