Does this document carry any weight with the tax authorities?

No, and it matters that you understand this.

The summary does not prove that the transactions actually took place. It simply calculates from what you entered: if a quantity, a price, a fee or a date is wrong, the result will be wrong too, and Earnnest has no way of noticing.

The only documents that carry weight are the ones your broker or bank issues: your account statements and your annual tax statement. Where the Earnnest summary and those documents disagree, the latter always prevail.

Our recommendation: use the summary to understand and prepare your return, then compare it against your broker's document before entering anything. If in doubt, or if your situation is unusual, consult a professional.