One of the main pros of giving monetary gifts over purchased goods is that it's easy to control spending. There is no temptation, once in a store, to buy something else to add to the gift or to buy a more expensive item than was originally planned. One of the major cons of giving a monetary gift is that there is sometimes no way of knowing for certain that the person received it.
For instance, many people add cash to greeting cards for a gift. Unless the gift giver is there to see the people open the card and view the cash, or he or she receives a thank you card or phone call, there is no guarantee that the individuals got the monetary gifts. If a check is given rather that cash, it's easier to track since the gift giver can watch for it to go through his or her bank account. The con is that a check tends to not look as exciting as actual, tangible bills for a gift, plus it's not as convenient, as the recipient may not be able to cash it that soon. At some banks, a person may have to have the check held for a week or more until it clears; sending a certified check may help solve this problem.
A pro of giving monetary gifts is that everyone typically likes to receive this type of present. This makes it a good solution for people who are especially difficult to buy gifts for, either because they have everything or they're picky about what they like. The recipient is free to spend the money or save it as he or she wishes. There is no need for the gift giver to spend time in a busy shopping mall or searching through online catalogs looking for the right present.
A con to giving a monetary gift is that, although it's usually very much appreciated, it lacks the thought involved in choosing a more personalized present such as a beautiful angel figurine for someone who is passionate about collecting them. Yet, the fact that monetary gifts are usually placed inside greeting cards is a pro since the gift giver may hand write something like "Happy Birthday. This gift is for you to pick out an angel figurine or whatever else you'd like."
Monetary gifts at weddings can be very much appreciated by the bride and groom. After all, weddings are typically expensive and the couple is likely to receive many gifts to use in the home. A monetary gift can mean that the couple has some extra spending money on their honeymoon or something to use to enjoy a romantic dinner out together.