Google Pixel comes is being offered in only three color variations – “Quite Black”, “Very Silver and “Really Blue”. This is a very limited range of colors, and the limited-edition 'Really Blue' will temporarily be a US exclusive. I am wondering why a color of a phone has to be exclusive to a specific region. I mean I know that they want US customers to buy it from Verizon which is an exclusive carrier partner in the US, but I'm sure that that frustrated quite a lot of people who put their eyes on this awesome blue colored phone.
Most people that I know put some type of cover over their phone. I use a brown/black cover on my iPhone, and because it's black, I really don't care about the original case color. I actually use the case to protect the device. There are tons of other colorful cases that you can use to cover your brand new Google Pixel phone. Some of those are designed by Google and have a matching live wallpaper, including one that resembles the screen of Google Earth and Google Trends applications, but there are many 3rd parties offering as well.
If you get the time-exclusive 'Really Blue' color Google Pixel phone, I'm pretty sure that you won't get it covered or at least use a transparent cover case so the blue color can shine can be seen through.
I personally really liked the Incipio Carnaby Esquire Series case that has fabric finish. Other cases will even protect your Google Pixel phone from accidental drops or protect it against water. If I got the 'Really Blue' version, I would probably go with the Speck Presidio Clear case, although it's quite expensive (~$40) - but it has a hard exterior layer and drops tested from 8 feet. It's slim and doesn't add a lot of bulk to the phone.
I think that many people will be frustrated by having a limited range of colors to choose from when they buy a new Pixel phone. Just in comparison, The competition isn't that impressive either in that regard. The Samsung Galaxy S7 comes in four colors in total: white, gold, silver, and black. Most phones have a black and white/silver color variations, but where this blue color came from? I think because it's unique and I can't recall a phone having such a bold blue color, many people will choose it over the others. When you walk with it in the street, people will know that you have a Google-brand phone, and not an iPhone (the Google Pixel really resembles the shape of an iPhone).
It would have been nice if we add more colors to choose from, and that's why I mark this as a disadvantage.