What is up with Mikael's?

seems to be the only option when it comes to support item purchasing. No matter what the enemy team's comp is. I've been told this is the only item to get even if the enemy team has no hard CC. I see the same in LCS and on twitch. I main support and I am in Gold IV at the moment and I still don't get why this is the end all be all item. I only get it when the enemy team has a CC chain combo (panth to ahri to moakai or similar) or long range CC engaging (Morgana, Zyra). It doesn't remove knock-ups (Janna, Nami) or suppression (Warwick, Malzahar) and the heal is nice but rarely makes the difference. It gives MR but no Health or Armor making the defensive stats situational at best as AD mids are pretty popular at this time and as a support I rarely ever have mana problems as I need to go back regularly to get wards anyway.

I would really like to understand is being chosen over or in almost all situations. I'm starting to feel that I'm missing out on something and would appreciate some insight as to why this item is so dominant.