Sorry to be so rudely blunt, but your disagreement simply reflects a profound lack of understanding of the way criminal law and investigations work. The investigation is ongoing. Until and unless they’re ready to indict and prosecute, there is an ongoing need to protect confidential human sources, cooperating witnesses, and other ongoing investigative steps. That affidavit may identify who came forward- someone whose testimony may be later required in court. It may identify who so far has and who has not given sworn testimony to a grand jury, and by extension who may subsequently be sought as a witness. It may identify locations and premises that could be searched still. It might identify ongoing PEN registers, wiretaps, or undercover operations. It could burn ongoing surveillance. It could expose evidence sought but not yet recovered that could be destroyed if known.
None of this is any material way different from other criminal investigations with a covert element. Sealed affidavits are both utterly and boringly normal, and essential to succesful investigations.
The fact that Trump had a big tantrum about his place being searched and announced the warrant to the world doesn’t mean he now gets to demand the investigation be blown open and everything revealed to him. Due process means, he like anyone else, has rights. Anyone else would similarly have to wait and see (though of course he could also ask his lawyers to file an argument to unseal the affidavit- something I don’t believe has happened).
In the meantime, the proper course of Justice demands that investigators and prosecutors be allowed to do their job, and that the status of a potential suspect not be allowed to obstruct their investigative efforts. If charges are laid, the affidavit will be unsealed. If the matter is concluded without charges, there will be little remaining argument to leave the bulk of the affidavit sealed. But so long as it contributes to be a viable criminal investigation, the confidentiality of that affidavit is essential to the proper course of justice.