Sadly, that is one thing PC users have over console/mobile players. We can access corners, but you literally can not. It allows us to fit more casks in the cellar, kegs in a shed, etc while still having access to them.
Actually, this got partly fixed in 1.5, at least for Switch (I don't know about the other platforms). Pre-1.5, you could only reach the bottom-left and bottom-right corners, so the most efficient setup was U-shaped. Now,
if you hold A, you CAN access all the corners. It doesn't work if you hold Y.
But the thing that bugs me the most? It doesn't work for Coffee Beans. Instead it shows the Placement Indicator (if turned on in the settings), as if you were trying the plant them (presumably because they are seeds first and ingredients second). This means that you have to line your Kegs up vertically and without corners to process Coffee Beans effectively, which is frustrating because the fastest way to process every other crop is to spread the Kegs out
horizontally! Even with vertical Kegs, Coffee Beans still take about 1.5x longer to fill Kegs with than horizontal Kegs and anything else.
Another side effect of the planting mechanic is that you have to arrange Garden Pots without corners.
But the biggest difference between consoles (again, I only have experience on Switch but I assume it works the same on other consoles) and PC comes down to planting, harvesting, and watering crops. On consoles, you can only plant on the same axis as the player, so no violent up-and-down mouse movement to plant above and below. So it takes three times as long to plant crops.
When it comes to harvesting, again 1.5 dramatically improved it. Pre-1.5 you couldn't harvest the crops above the player, only the crops inline and below the player. Now, while standing in one spot, you can harvest the 3x3 around the player (with a little bit of joystick nudging). It is also
noticeably faster to harvest from left-to-right than right-to-left, because of an animation glitch.
Out of the three farming interactions, watering is the slowest compared to PC. On console, you can only water the tile directly in front of the player. So no 3x3 from one spot like you get on PC. The best you get is a 4-tile diamond shape (like a basic Sprinkler), and even this takes significant joystick-handling skills to do without leaving the tile you're standing on.
Combining all these things (and animation-canceling not being present on consoles, although I don't ever expect it to be), the farming scene is far inferior on consoles than it is on PC. I would say that it takes about
four or five times longer to harvest, replant, and water crops on console. Whenever someone says that they manage 100+ crops at one time in their first Spring, I immediately assume that they play on PC.
TLDR: Yes, you can put most things in equipment diagonally, but there is still a long way to go before consoles players can farm at an equal speed as PC players.
[EDIT 17 Dec 2022] Cleaned up a bit, made clearer.