This is because gerunds is used to express an action that is happening and often the person thinks that is the only use. It can also be used as a noun or adjective. Sometimes the gerund may be used to introduce a noun phrase like, “Ordering in a restaurant is difficult especially when it is crowded.” The average person probably thinks that the gerund is only used in the present tense in order to relate an on going activity. If you were in the process of doing something, you would need to express yourself using the present progressive or present continuous tense. This would also apply to something that is going to happen in the near future. So if I say, “She is playing the guitar,” that is something she is doing at time the person is speaking. The gerund can also be used in the past to generate a sense that the action had occurred then.
When the gerund is an adjective, it would be used to describe a person, thing or event. So if I said, “The concert was boring,” by inference, I would be saying that I did not find the concert interesting. If I wanted to get an opinion about a certain sport, I could say something like, “What do think about skiing?” Skiing would then be a gerund form of the activity and is the noun in the sentence. I might want to suggest that someone try a certain sport and here again I can use the gerund form of the verb as in, “How about trying hockey as a sport?” There are many uses for the gerund then that can be tailored to the means of communication the speaker wants to use. The gerund may also be incorporated into idiomatic expressions.