Beginning something new, a company, a fund, a venture of any kind, is a moment of intent and optimism. It is also, almost always, a moment of new exposure, and the two are easy to keep separate in one's mind when they should be considered together.
A new venture generates records quickly. It is registered, and the registration names those behind it. It requires an address, and the address enters the record. It may need to file information, and filings are open in many places. It is frequently announced, because announcement is part of how a venture begins, and the announcement names its founder and describes their role and ambition. Within a short time of starting, a person has created a fresh and well-documented connection between themselves and a new entity.
That connection then does what connections do. The new venture becomes a point linked to its founder, and through the founder to their other interests, and through those to a wider picture. For someone studying an individual, a newly formed entity is valuable precisely because it is new: it is current, it is documented, and it often reveals present intent in a way older records do not.
There is also the matter of sequence. Exposure created at the moment of founding is difficult to address later. A name, an address and a relationship placed on the public record at the outset tend to stay there. Decisions about how a venture is structured and held are far easier to make thoughtfully before it is formed than to revisit afterwards.
None of this is a reason to begin nothing, which would be absurd. It is a reason to treat the launch of a venture as a privacy decision as well as a commercial one, and to make the structural choices early, with a clear view of what the new entity will, by simply existing, place on the record about the person who founded it.