Hearses have their own very particular aesthetic, and it's one that's mixed with a given culture's end-of-life traditions, and as such we tend to give them a free pass, styling wise. But not today. Because someone has to tell the hearse community that Landau bars make no fucking sense on them.
Let's just get our facts straight here: hearses are, essentially, big, luxurious station wagons that are designed to haul exactly one kind of cargo: a coffin and its very calm occupant. Landau bars are a strange old coachbuilders' affectation that came around in the early part of the century as a way to make cars appear to be convertibles when they weren't.
See, the original source for the "long-S" looking bit of frippery was actual hinged bars used on convertible tops in horse-drawn carriages. Car makers were using these on vinyl roofs to fake people out into thinking the cars were convertibles (ha ha! Gotcha, sucker!) as early as the teens and really exploded in the late '60s and early '70s.
So, if we follow the logic of Landau bar use, the placement of that huge landau bar on a hearse is to suggest that the hearse is a convertible.
As in you can fold that colossal roof, and let your dead body in the back enjoy the sun. Hm.
I know Landau bars have just sort of morphed into this goofy ornament that just reads as "classy," but it's classy in that cheeseball way that large photographs roses on piano keyboards are "classy." In that they're awful.
So, before your next hearse purchase, I implore you to forego the Landau bars. They make no sense.