Sending a text is the most efficient way to say "I love you, just not enough to call."
I would like to offer another view on this. If the recipient doesn't react well to sudden phone calls, but is calmer with text because they can control the pace a little more. Then my choice to text is because I have been able to take the time to understand this preference for this person.
So, I feel, as with many and most things... It Depends.