What is the effect of locale on numbers?

Hello.

I use swedish locale

show lc_numeric;
 lc_numeric
-------------
 sv_SE.UTF-8

and I get a . (dot) in all floating-point numbers.

This makes me wonder, when can I see the effects of the locale? That is, I get

select 355/113.0 as pie;
        pie
--------------------
 3,1415929203539823   <---  notice , instead of .

instead of

 3.1415929203539823