[RPG] Does a clay golem’s haste action actually give it more attacks

A clay golem has an action called Haste that is thematically similar to the spell of the same name but mechanically rather different:

Haste (Recharge 5–6). Until the end of its next turn, the golem magically gains a +2 bonus to its AC, has advantage on Dexterity saving throws, and can use its slam attack as a bonus action.

At first glance, this appears to grant the golem one additional attack (as a bonus action). However, using the ability costs the golem its action, with which it could otherwise make 2 slam attacks. Since the ability lasts until the end of the golem's next turn, it can attack with its bonus action on both the turn it uses the ability and the following turn, yielding a total of… 2 additional attacks. Thus, it seems that over the course of these 2 turns, the golem will get 4 attacks, regardless of whether it uses its Haste ability or not. The only difference is that with Haste, one of those attacks comes 1 turn later.

So, am I correct in finding that the net effect of the golem's Haste action is to delay one of its attacks by one turn in return for improved defenses for 1 round, as opposed to actually granting additional attacks? Obviously there are cases where this is unambiguously a benefit, e.g. when the golem can't get into melee on the current turn, but I suppose I find it a bit surprising that, if anything, the golem's Haste action causes it to attack more slowly.