Performance Improvement:

ActiveRecord::Calculations methods are optimized for database-level calculations, which can result in more efficient queries.
Using Loan.minimum(:amount) or Loan.maximum(:amount) often translates to a single SQL query, while Loan.pluck(:amount).min or Loan.pluck(:amount).max involves fetching all records and performing the calculation in Ruby.

Readability:

The intent of the code becomes clearer when using minimum and maximum directly, making it easier for other developers (or even yourself) to understand the purpose of the code.

Code Conciseness:

The alternative code (Loan.pluck(:amount).min or Loan.pluck(:amount).max) is longer and involves multiple method calls. Using minimum and maximum directly makes the code more concise.

Consistency:

Favoring ActiveRecord::Calculations methods promotes consistency in your codebase. Developers working on the project will use a standardized approach for such queries.

Compatibility:

As Rails evolves, methods like pluck followed by min or max might become less favorable or less efficient. Using the recommended ActiveRecord::Calculations methods ensures compatibility with future Rails versions.