It's more accurate, especially since heart rate is almost universally measures in beats-per-minute, than, say, timing your pulse for a [factor of 60] seconds (30 seconds, 20 seconds, 15 seconds, 12 seconds, etc.).
Answer: The advantage of timing your pulse for a full minute is you get your pulse exactly beats per minutes vs an estimate.
Explanation:
Normally pulse rate is calculated for 15 seconds and then multiplied by 4. But this case may lead to inaccuracy, as the pulse rate may vary over the time period of one minute. therefore, it is best to find the number of beats per minute instead of 15 seconds.
