there are numerous reasons of which i'll try to name a few and others can fill in the blanks...

for one it gives you another card. Any club or A improves your hand. Villain might shut down and be less inclined to believe his hand is good if he's holding anything but a set or big overpair. Either way his action on the Turn will give more info.

It also gives him a chance to bluff off more chips on the Turn with hands like KK, QQ, AJ, KJ, QJ, TT, 99 or the non-nuts flush draw - hands which you are currently beating. You can see how folding if he's holding any of these hands would be a big mistake.

Shoving all ur ships in makes him fold the majority of these holdings, with the exception of KK or QQ (MAYBE) and you're usually only getting called by hands that crush you like JJ or even 55.

Hence calling is prob your best line. (from my understanding)