It shows how much Mihawk alone is worth.
Look at how long & what it took Yami + Gura BB after the Marineford exploits to cement his place as an Emperor.... he needed to gain territories & overwhelmingly crush Marco & the WB remnants to even get into the conversation. And after 2 years, he still has a meagre 2.2 Billion despite having a crew full of Impel Down Lvl 6 monsters & Shiryu who are also growing stronger.
Now look at what Mihawk joining did to Cross Guild.