Rationale for not scoring a 4-card crib flush?

I am new to the game of cribbage and am curious about the conspicuously negative rule excluding four-card crib flushes. This rule seems to be begging for a good mathematical explanation. Statistics seems like the right explanation, but the five-card crib flush is very improbable and intuitively does not seem to justify a special rule excluding the four-card flush.

Flush

Not sure what the question is here. Four card flushes are scored in hands. In the crib only you have to have all five cards of the same suit to score a flush.

So last night I was playing

So last night I was playing cribage and I got 7 8 10 J of clubs and the 9 of clubs was the flip card how do u score that seems how it's a royal flush?

No such thing as a royal flush

There is no royal flush in cribbage. The hand you described is 2 pts for 15, 5 for a run, 5 for a flush and one for the right jack for a total of 13 points.

Cribbage

You would have scored 15-2, 5 for your straight and 5 for your flush, for a total of 12 points.

It's simply a matter of

It's simply a matter of rules. It's not about math or statistically what is likely to happen. It's just to make game play a little more difficult and therefore, a little more fun. It's been that way since the game was created.

? About a flush when counting

I am still aware that u cannot call a flush when playing, which i do not like as far as rules go. But, when scoring after all cards are played, what if u hold 3 suited cards in your hand, and the starter card is a matching suit. Can u call a four point flush? Even though all the cards in your hand may not be the same suit? For example: i hold 3, 6, 7 of hearts and a 3 of clubs in my hand and the starter card is also a heart....?

? About a flush when counting

I am still aware that u cannot call a flush when playing, which i do not like as far as rules go. But, when scoring after all cards are played, what if u hold 3 suited cards in your hand, and the starter card is a matching suit. Can u call a four point flush? Even though all the cards in your hand may not be the same suit? For example: i hold 3, 6, 7 of hearts and a 3 of clubs in my hand and the starter card is also a heart....?

Flushes

Rules on flushes are very clear. When you count your hand after pegging, if ALL of the cards in your hand are of the same suit, score one point for each card (4 points), if it includes the starter card score a total of 5. Flushes in the crib require the starter card and as such are very rare. You cannot take a flush during pegging and you cannot take a flush that is less than all of the cards in your hand being of the same suit. www.cribbage.org