You'll still get more output for the same amount of panels when they're tilted in most places.
This guy did some interesting real-world testing in a bunch of different circumstances - https://www.youtube.com/watch?v=5AVO1IyfA9M
This guy did some interesting real-world testing in a bunch of different circumstances - https://www.youtube.com/watch?v=5AVO1IyfA9M
The other major advantage here is that you can use them with farming and actually do something with the space.
In addition areas where it snows sees a dramatic uptick in solar power because of the reflection of the snow and not needing to brush the panels off.
vertical panel layouts really open up a LOT of options that were not available before. (using them as fences, putting them on sun facing walls of homes spaced off and letting the pass through sunlight hit the other side). There's a lot of possibilities here).
So vertical makes a lot of sense on large scale solar farms I think, even more so when you consider the land can be better utilised.
On domestic scale, where you can easier shift your load to match your production AND you might already have a roof with the right front and pitch, normal pitched north/south facing installations might make more sense.