By removing the SD slot on the new MacBook Pro models Apple just screwed every photographer I know (including myself). You can add to that countless video editors.
Yes, you can use an adapter and it may seem like a trivial thing, but it's the sort of little thing that rubs people very, very wrong and breeds a lot of resentment, because it makes your life just a little more inconvenient.
Between the removal of the headphone jack on the iPhone and now the removal of all widely used ports on the MacBook Pro lineup we are going to be drowning in adapters.
If you plan on charging your iPhone from your computer you will need a USB-C -> USB-A adapter to use your existing Lighting cable. Yes, you could buy a USB-C to Lighting cable, but that would lock you out from the billions of existing USB-A ports we charge at in daily life (Airports, the office, cars etc). Add to that a Lighting -> Lightning Splitter / 3.5mm adapter if you insist on using your existing headphones and want to recharge at the same time.
Most of us are probably going to end up carrying around some sort of dock to make up for the loss of widely used ports on the new MacBook Pros, which completely negates any gains made by Apple shaving off another few mm in thickness. Remember when you could just slip your MacBook Pro in a sleeve and go? Say goodbye to those days, because you're either going to be carrying around a small dock or multiple adapters or special cables.
You are probably going to need:
USB-C -> Magsafe syle power adapter.
USB-C -> HDMI
USB-C -> Mini displayport
USB-C -> USB-A
USB-C -> Micro-B SuperSpeed (external USB3 drives)
USB-C -> Thunderbolt2 ($49)
It's completely insane.
People are constantly sharing data via USB sticks and external drives and everything is going to need an adapter, until you spend hundreds of dollars rebuying everything. It is going to take YEARS until USB-C has anywhere near the market penetration that USB-A has. Just because you may decide to upgrade all of your peripherals does it mean that the rest of the world will follow suite anytime soon.
Would it really have killed them to keep the SD slot and at least ONE USB-A port for one more generation to ease the transition, just like they did with Firewire and Thunderbolt?