Should old derelict buildings be destroyed or persevered?

Bandstands are unused anymore. They just sit there and nobody has used them in a century. A baths place near me was unused for 30 years till they turned it into a cafe.

Dun laoghaire baths
Dun laoghaire baths
Blackrock baths. Last used 1987 and the diving board is gone now.
Blackrock baths. Last used 1987 and the diving board is gone now.
bandstand. There are 3 near me unused in a century.
bandstand. There are 3 near me unused in a century.
Should old derelict buildings be destroyed or persevered?
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