MySQL with JDBC - useUnicode needed?

Question

In a lot of places, it is noted that if you want to use JDBC with MySQL and have support for UTF-8, you need to add useUnicode=true in the JDBC URL.

E.g.:

• JDBC MySQL UTF-8 string writing problem
• problem with utf8 in java

However, I tried this locally using MySQL 5.7.19 on Mac OS X with mysql-connector-java 5.1.41 (pulled in by Spring Boot 1.5.3). I added a file /etc/my.cnf with:

[mysqld]
collation-server = utf8_unicode_ci
init-connect='SET NAMES utf8'
character-set-server = utf8

This makes sure MySQL is set up for UTF-8:

mysql> SHOW VARIABLES LIKE 'character_set%';
+--------------------------+-----------------------------------------------------------+
| Variable_name            | Value                                                     |
+--------------------------+-----------------------------------------------------------+
| character_set_client     | utf8                                                      |
| character_set_connection | utf8                                                      |
| character_set_database   | utf8                                                      |
| character_set_filesystem | binary                                                    |
| character_set_results    | utf8                                                      |
| character_set_server     | utf8                                                      |
| character_set_system     | utf8                                                      |
| character_sets_dir       | /usr/local/mysql-5.7.19-macos10.12-x86_64/share/charsets/ |
+--------------------------+-----------------------------------------------------------+
8 rows in set (0.00 sec)

Now in my application.properties I tried with:

spring.datasource.url=jdbc:mysql://localhost:3306/testdb

and

spring.datasource.url=jdbc:mysql://localhost:3306/testdb?useUnicode=true

But in both cases, it seems to be ok. So: is the advice to add useUnicode=true still valid?