What makes buying insurance rational?

Hey, ev­ery­one! So I’ve been read­ing an ar­ti­cle about the ex­pected util­ity, ap­par­ently to figure out whether the risk is worth tak­ing you mul­ti­ply ex­pected value of the out­come by it’s prob­a­bil­ity.

And ap­par­ently in­surance com­pa­nies can make money be­cause the ex­pected util­ity of buy­ing in­surance is lower than it’s price.

So why would buy­ing in­surance be the ra­tio­nal ac­tion? I mean in­tu­itively it makes sense(you want to avoid the risk), but it doesn’t seem to fit well with this idea. If in­surance is al­most by defi­ni­tion is worth slightly less than it’s price, how is it worth buy­ing?

(sorry if it’s a dumb ques­tion)