I think it also created the situation where, despite the Tory's efforts ("There's no magic money tree!"), it caused people to take a greater look at the Labour manifesto in contrast, and many found themselves surprisingly liking it.
Brexit was supposed to make the country better off according to the proponents, so for a cabinet of Brexiteers to present a manifesto that paints the country as needing to cut back even more once we're out of the EU was always going to go down like a sack of shit.