When using another decimal separator than `.` (dot)
in the language settings,
it wasn't possible to build an advanced search specifying
the decimals.
e.g. with a language with decimal separator `,` and thousand
separator `.`,
if you want to search invoices with amount total 366,38
The advanced search "Total" "is equal to" obliged you
to enter your number with `.` as separator (366.38),
and then, when entering the search, the `.` was
regarded as the thousand separator, giving as domain
`('amount_total', '=', 36638)`, which is not what you asked.
opw-634201
PS: The `|| '.'` in the xml template are only for
retro-compatibility, so if the server sources are
updated, but the browser cache is not refreshed
(meaning the Javascript code isn't refreshed, and,
therefore, `widget.decimal_point is undefined)
it still works.