Is it permissible to benefit from the price difference offered as compensation, instead of purchasing the original item that was not delivered, with the intention of not buying the item and benefiting from the amount?

As long as the entity pays the compensation voluntarily, there is no objection for you to spend the compensation amount on a purpose other than purchasing a similar item to the original one. It appears that mentioning a similar item is to determine the amount of compensation, not to oblige you to buy one like it. The questioner can verify with the customer service of the compensating entity whether they stipulate the purchase of another item or not.