I believe this is a good exercise, because right off the bat attention is being paid to pitch and tone. Many questions I have seen posted on various clarinet bulletin boards deal with problems such as flatness of pitch, problems with intonation, etc. These are problems that, if treated early, can be permanently solved. This exercise will also promote good tone quality, and is an important part of early development. Another valuable exercise, using the entire horn, is long tones.
Long tones are excellent for developing a sense of intonation and improving tone quality.
While I really won't give a set regiment of specific long tones, I would recommend some kind of thoughtful approach to playing them. For instance, one could play a major scale in long tones, perhaps arpeggios, whatever suits you. Just make sure that you work out an agreeable exercise and use it consistency. Listen to what you are doing, and how the tone is produced. Make small adjustments and observe.