1. Boomer rock voters may just vote for boomer acts before and may dislike sound of Maiden, but they have to vote for 7 now and if they just don't want to choose any pop/rnb/rap act, they just have to choose Maiden as they are guitar band.
2. General voter or even black voter, they may choose Maiden as #7 pick despite don't like or even never hear of any Maiden song, they vote because they think Maiden is iconic metal band...
This is first time true metal act in the ballot that voters can (must) vote for seven. And Maiden has basically zero competition this time (Motorhead, JP all had huge competition in heavy rock when they nominated, Maiden last two nominations faced heavy rock acts as well). Definitely possible for Maiden to grab #5-#7 and included as main performer.