The benefit of a no comment interview is that it allows you and your lawyer to formally respond to the allegations once all of the evidence has been collected and is presented in a brief of evidence. Your lawyer can then advise your lawyer as to whether you will plead guilty or not guilty, having had the benefit of your lawyer's appraisal of the prosecution case, in particular an assessment of the strength of their case. An informed decision to plead guilty can always be made at a later stage whilst still receiving the benefit of pleading guilty - there is no need to rush into such an important decision!
At the conclusion of the interview the investigating police will need to decide whether you are to be remanded in custody, bailed, or released pending summons.
The decision to remand you or release you is not based upon whether you did or did not answer their questions, but rather the nature of the allegations, and your criminal history, and bail history. The prosecution case will always rise and fall on the strength of the evidence that underpins the allegations, and not whether you answer their questions or not.
People often feel more comfortable telling police that they are giving a no comment answer on the basis of legal advice. This simply makes it clear that you are not being unhelpful to the police investigators, you are simply following legal advice.
As all the questions and answers are recorded it is important that you do not convey that you are being selective with your answers. That is, you must ensure that every question is answered "no comment" and that you do not answer some questions (because they seem harmless).
The police interview is simply another mechanism for gathering admissible evidence in support of the charges (through an admission, or confession). An accused person's is almost always at a disadvantage as compared to the investigators at an interview. This is because often particularly in regard to serious offences (such as historical sexual offences) the investigation has already reached an advanced stage. Put simply, the prosecution will already be considered and digested a body of available evidence before the interview commences. Moreover, they are professionally trained in interview techniques that will elicit information from you which may support their case. Often, they will have planned the format of the interview (and again particularly for serious offences) well before you arrive at the police station
There are some exceptions to the general rule that a no comment response should be given but these circumstances are rare, and a departure from the general position ("no comment interview") should only be considered after your lawyer has undertaken a thorough analysis of your circumstances and instructions well before the police interview.