It is unnecessary nowadays. Saskatchewan doesn't do it. Sir Sanford Fleming created it mainly because of train schedules. From Wikipedia:
"After missing a train while traveling in Ireland in 1876 because a printed schedule listed p.m. instead of a.m., he proposed a single 24-hour clock for the entire world, located at the centre of the Earth, not linked to any surface meridian.[12] At a meeting of the Canadian Institute in Toronto on February 8, 1879, he linked it to the anti-meridian of Greenwich (now 180°). He suggested that standard time zones could be used locally, but they were subordinate to his single world time, which he called Cosmic Time. He continued to promote his system at major international conferences[13] including the International Meridian Conference of 1884. That conference accepted a different version of Universal Time but refused to accept his zones, stating that they were a local issue outside its purview. Nevertheless, by 1929, all major countries in the world had accepted time zones."