Exactly. And it so integral to a 1099 that there is literally a dedicated line on both Sched C and E to report “Commissions and Fees” as an expense.
It’s all about documentation so the IRS wants to see all of those details.
It’s not a matter of benefit, either Schedule C is the correct form or Schedule E is the correct form depending on the details.
But it is possible to need to file both if you have different activities. My Airbnb 1099 goes on Schedule C as a business activity but my apartments-com 1099, which is rent/deposits/fees received from tenants, goes on my Schedule E as a rental activity. My point being that either way there is a place to deduct commissions and fees because payments reported on 1099s so commonly include them even though they are expenses and not income.