目覚め時計をセットした時間に起きなきゃ意味がないって英語でなんて言うの？

Both of these answers question the point of someone setting an alarm clock if they don't wake up when it goes off.

If something is "pointless," it has no use or purpose. An alarm in American English can ring or go off. I hope that this helps! :)

Bother and get up mean
Bother - to take the time, the effort, or the trouble to do something, such as setting an alarm. So you should not bother or take the time to set the alarm if you are not going to respond to it.

Get up - To wake up from sleep and leave the bed.

To ask a question you could say you could rephrase the statement to ask,

"Why do you bother setting an alarm, but you do not get up?"

Any one of these sentences can be used :-

1. What's the use of setting the alarm clock if you're not going to get up when it rings?

2. It makes no sense setting the alarm clock if you don't wake up when it rings.

   When we use the phrases "what's the use....." or "it makes no sense to do....."means that we don't see the logic behind the action we are taking.

In order to explain that it is completely pointless to set an alarm clock if you don't wake up when it rings, you can state "There is no point in setting the alarm if you don't get up when it rings". This sentence explains that there is no logic behind creating an alarm if you will not use it for its purpose.

The two sentences you see provided above are terrific ways to express to your listener that there is no meaning in setting an alarm if you aren't going to wake up when it goes off. The second sentence is in the form of a rhetorical question. This type of question is used to emphasize a particular point or make a statement rather than get information.

If you are talking to someone else where an alarm is ineffective say "Why would you set an alarm if you don't wake up when it rings?". This puts the emphasis on them to explain why the alarm doesn't work but they keep using it. If it is you than you can say "I don't set an alarm because it doesn't wake me up".