What is the significance of transient hypertension?

None. Everyone has transient hypertension and it's not a disease. Our normal physiology is to increase BP in response to stress, discomfort, excitement, activity, anger, fever, etc. The disease we call "hypertension" is diagnosed when resting BP (or "basal" bp) remains elevated for no reason.
May be normal. If the elevated blood pressure is truly transient, it may just be "white coat hypertension", induced by anxiety or stress. Although not entirely benign, it is certainly less serious than persistent high blood pressure. Home BP measurements with a calibrated BP device, or better, ambulatory 24 hour BP monitoring, can sort it out. Night time bps, if elevated, may convey greater risk.