It's not always the case, blink is good no doubt, but jumping into them isn't exactly a risk people should take. For instance, Patrick Casey form PlanetDestiny mentioned how he fought blink shotgunners in particular on several occasions. The tactic was that blink users would blink towards you, pull out a shotgun, and let gravity do the rest until they had to pull the trigger. The shotgun user would be right above you and all they simply do is fall on top of you, but by the time you realize they're above you, it's too late. Patrick would run forward should the shotgunner use blink, going under the shotgunner, and giving him enough distance to use his primary and a throwing knife, whilst the shotgunner has to compensate for the distance gained from his/her said target.