Would this have applications on big billboards?
Probably not, as the technology has no backlighting and would not be visible at night. Think of Minority Report-style cereal boxes, that’s the level of ubiquity this stuff will eventually end up having.
Luckily, that ought not to happen till we have a little more progress on the battery front. In the meantime, expect in-store advertising displays, trade show publicity gimmicks, and the odd trendy magazine cover.