It makes sense to still have some "dumb" unguided weapons as a backup, as homing weapons' sensors can be jammed and fooled to go after decoys, while a depth charge that simply drops down to a given point and blows up cannot be easily interfered with in any meaningful way, you can't even locate it using only passive sensors, because it is virtually noiseless apart from the very brief noise it makes when entering the water.
Also, as someone else mentioned, you can easily fire an unguided weapon in such a way that it deliberately misses the target, as a warning.
If anyone is looking for a good reason for being ashamed of being German, don't look any further than his guy and his party.