One of the the benefits of American Express Business Platinum card is Gold Status with Starwood Hotels, etc. (SPG). But because of Marriott and SPG merger you can link accounts in those two programs to match status across both programs, effectively giving you Gold status in Marriott rewards program. You can read more on how to link SPG and Marriott accounts in SPG Marriott/Ritz-Carlton Rewards Points Transfer and Status Match post.
Marriott Gold Status comes with a variety of Perks that can be found on Marriott Gold Elite Benefits page.
The most valuable ones : free breakfast and guaranteed late check out. The forum on flyer talk blog keep track of all domestic/international executive lounges open/closed/weekends statuses. Check it out before booking your Marriott reservation.