What is the meaning of pallet::compact in Pallet development

Question

In this code, we can see the pallet::compact is used. So why we need this instruction?

quotes code:

#[pallet::weight(1_000)]
        pub fn transfer(
            origin: OriginFor<T>,
            to: T::AccountId,
            #[pallet::compact] amount: T::Balance,
        ) -> DispatchResultWithPostInfo {
            let sender = ensure_signed(origin)?;
            let sender_balance = Self::get_balance(&sender);
            let receiver_balance = Self::get_balance(&to);

            // Calculate new balances.
            let update_sender = sender_balance.saturating_sub(amount);
            let update_to = receiver_balance.saturating_add(amount);

            // Update both accounts storage.
            <BalanceToAccount<T>>::insert(&sender, update_sender);
            <BalanceToAccount<T>>::insert(&to, update_to);

            // Emit event.
            Self::deposit_event(Event::Transferred(sender, to, amount));
            Ok(().into())
        }

Answer 1

pallet::compact is just a "shortcut" for writing Compact<T::Balance>.

Compact is a wrapper defined by parity-scale-codec to compact integers when being stored in their encoded format. So, that the entire transaction is a little bit smaller.