Generally speaking, condensed milk is a kind of dairy product with strong sweetness. Adding it to coffee will neutralize the bitterness of coffee and bring a silky and sweet taste. However, if condensed milk is added too much or too thick, it may make coffee too sweet and greasy, and even cover up the original aroma and taste of coffee.
Generally speaking, condensed milk can be added in moderation according to personal taste, but it is not recommended to overdo it.