TinyTranslations handles locale files, styles, messages and per player locales for you. Even if you code plugin for your own server and consider hardcoding language strings, you'll benefit from switching to TinyTranslations, because you don't have to rebuild jars for corrections such as spelling mistakes.
TinyTranslations introduces style sheets while at the same time using MiniMessage and Adventure. This for example allows you to apply different color schemes for different seasons.