It is considered architecturally and design-correct at the moment to use white or grey walls. Even these pale tints have their warm or cool undertones though. Nevertheless, they are the easier choice, and here's why.
When choosing to paint your walls a colour, there are many things to consider. First, what is the orientation of your room - north, south, east or west? A southern exposure will add warmth to your chosen colour, while a northern one will add coolness. In addition, you will likely be turning your lights on before 5 pm in December, while in June, not before 9 pm, and that means the quality of your lighting will also affect your colour.
However, now that we have access to both halogen and LED lighting which reproduce colour accurately, that is not the same problem we have when we use incandescent which tends to add a warmer quality to colour.
In addition, it is also a challenge to create flow between rooms when using colour on walls. Flow is a design fundamental. In a small 2-story house, a separate colour may be chosen for each floor, but they must relate to each other. It is also very important that they share the same strength or saturation of colour.
I noticed early on in Interior Design school while drawing elevations, that it is so easy for a room to look as though everything is sitting there on the floor. Making a room pale throughout will indeed solve this problem. Once you introduce any colour at all in your furnishings, a way to combat this bottom-heavy look is to introduce a very large and vibrant piece of art, if you can afford it.
On the other hand, using colour on the walls gives you a big leg up in creating your own 3-dimensional piece of art, i.e. your personal living space. As they say, paint is the cheapest way to make an impact.
May I remind you that from St. Petersburg, Russia to London, England to Rome, overall colour is a historical norm. Even here in Toronto in the Victorian age when so much residential building occurred, rich colours were favoured.
Here are 3 examples of wall colours I have chosen for Toronto houses, each with both cool and warm undertones to look well in any season. Both the teal and "Radiant Orchid" are medium tones, while the dark green room is rich and moody with layers of colour and pattern.
In my opinion, using all-over white or grey is the easier solution, no more, no less.
