Just like standard playing cards, the Mexican equivalent can be used either for playing card games or for divination.
The “Gallo” card you sent identified the deck you own as being a design of Clemente Jacques “Marca Gallo” cards which were first published in the 1920s. These are regular playing cards and are not associated with tarot cards or other decks that are typically used for divination purposes.
However, it should be noted that any playing cards can be used to divine the future, a practice known as cartomancy. This is one of the oldest forms of fortune-telling and is strictly forbidden by the Almighty who condemns all practices aimed at “unveiling” the future (Catechism No. 2116).
“Do not go to mediums or consult fortune-tellers, for you will be defiled by them.” (Leviticus 19:31)
For instance, Spanish decks, known as the Baraja Espanola, which look similar to the cards you sent us, are typically used for divination purposes, as this site describes.
“If you need a quick answer to your question, you simply need to draw one card. A single card can give an overall impression about your problem. If necessary, you can draw an additional card to clarify the first card . . . . For example, drawing a Hearts card means that issues to do with emotions and the home are going to be important that day, drawing a Diamonds card means that issues to do with hard work and affairs outside the home will be important, drawing a Clubs card means that issues to do with business and money will be important, and drawing a Spades card indicates problems and difficulties will be important.”
This might all sound like hocus-pocus, but resorting to hidden powers is dangerous and the act of using these cards is enough to summon spiritual entities whose only interest in our future is to destroy it.