The following is based on my reading of the agreement, but I am not a lawyer and this is not legal advice.
TL;DR: The "Credit Reference Agency" part of the Equifax corporation will be collecting all that data anyway (as all "the big three" agencies do); what you are agreeing to is for the "myEquifax" part of the company – and anything involved in providing the infrastructure behind the website – to have access to that data.
From the preamble of the agreement:
We note that EIS provides the "Credit Report": it is the body that collects and collates all your "credit-related" information and provides it to lenders, banks etc. as part of their main commercial operation. The collection of data for that report, and the provision of it to interested parties is not affected by this agreement.
The first clause of the agreement ends with some definitions:
- [...] EIS and its respective service providers are collectively referred to in this Agreement as "We," "Us," and "Our." You, the person visiting and utilizing this Site or to create an Account, are referred to as "You" or "Your".
So "We", "Us" etc. mean both EIS (the collator of your credit report) and the service providers behind the myEquifax website and services (which may be other parts of the Equifax corporation and, possibly, third-party companies providing the infrastructure behind the website).
Therefore, in the section you quoted, you are agreeing that the "Us" that will have access to all your personal information includes both EIS (which already has access to pretty much all your personal information) and anything else necessary to provide the myEquifax website/services.