What is the rationale for inserting 'a' before the noun 'value'?

The Company shall not submit tender for new business having a value of less than some specific amount.

However, when the noun 'value' is used to mean how much something is worth in money for which it can be exchanged, it has both countable and uncountable meaning. I always use 'a value of' without understanding the reason for that.

Would you please be so kind explain me the rationale of 'a' in this example? For example, why cannot zero article be used instead?

I would be grateful if you could explain me the general rule and the exception from that rule, if any, applicable to such an example. Would you please also state any other similar examples that follow such rules.

If something has value, it is valuable.

If something has a value, it has a particular value, such as \$500.

The use the word value with or without an article/determiner depends on the context.

So if you picked up an ancient coin and took it to a numismatist, you might ask any of the following:

1. Does it have value?

This question is asking whether it has some monetary worth or none.

1. Does it have a value?

Here you want to know rather how much it might be worth rather than just whether it has any worth at all.

1. Does it have any/some value?

This is really a way of asking whether it has any worth to speak of, very much like the first.

In your example, the reference is to a value, which is the way of introducing specific amounts, as the sentence states.

So, having value means have some unspecified worth.

Having a value is generally used when worth is specified, as in: Having a value of £1,000. or Having a value of more than £1,000.

Then you might say: The value of this object is £1,000.

In practice, most people might simply ask is it valuable?, which is the same as asking does it has value.