[Tagging] which wiki template for keys?

[Martin Koppenhoefer]

Some time ago I noticed people starting to change the key templates on wiki pages from {{key|example}} to {{tag|example}} (which displays just the same, the tag template is capable of working like the key template as well).

Recently I noticed people reformatting key references the other way round, from tag to key.

Which variant is preferable? Does it matter and why?

Cheers Martin