Are there consequences to running a 'long day' game?

Stuff you'll want at night:

• Sleeping mobs (Beefalo for hair, tallbirds for eggs, dangerous mobs for passing by safely), but you can put them asleep with darts or flutes, or just kill the mobs for the loot / safe passage.
• Finding fireflies (to relocate them, or make/refuel the miner hat)
• Losing sanity (but there are plenty of other ways to do that)

Usually, the shorter the night the better/easier, except for the fireflies.

There are things that can only be done at night. For instance, beefalos only sleep at night and while they are sleeping, you can take their hair for crafting hats and other items.