In this case they are easier to redevelop compared to, say, an old industrial complex where land contamination may be an issue.
Each gasometer was redesigned into a complete urban space by a different architect.
My apartment overlooked one of the hollow central 'cylinders': not much sunlight reached the interior, and - without net curtains - not much privacy (since neighbors opposite had a clear view across the space).
After seeing a huge crowd queuing in the lobby one evening, I realized the basement was used for rock concerts! And yet, not a sound (or vibration) reached the residential areas above.
Great place to stay for a while...