never use a number data type if calculations aren't going to be performed.
That sounds a bit absurd. Perhaps there is some context around that statement that you're not providing here?
Short text field size can be considered dynamic if I understand the M$ documentation on data types. It's used space is equivalent to what is required to hold actual values. The field size limits only govern the maximum number of characters that can be stored. So maybe you can save some space over a few hundred K or millions of records. On the other hand, if you use numeric types of byte, integer or long (1, 2 and 4 bytes) you might be using 4 bytes (long) when storing 2 when you could use far less by storing 2 as text.
However as far as I'm concerned the payoff with using numbers is that they follow logical order (otherwise text 111 comes before text 2) and you may decide to sum/average with them later on. Cannot do that with numeric values that are text. Trying to order numbers as text is a not too uncommon problem posted in this forum.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.