Why some function are class-less?

[Stefan Koch via Digitalmars-d-learn]

On Thursday, 17 November 2016 at 17:42:44 UTC, Suliman wrote:
> On Thursday, 17 November 2016 at 16:46:37 UTC, Steven 
> Schveighoffer wrote:
>> On 11/17/16 11:28 AM, Suliman wrote:
>>> [...]
>>
>> D does not require classes to write functions. All a class 
>> member function is anyway is a function with an implied class 
>> instance parameter.
>>
>> -Steve
>
> Ok, but what profit? Could you give me an example (for example 
> with logger)?

for example writeln.
You would not want to create a stdio object just to call writeln.