Providing i18n functionality is NOT the role of Phalcon. Phalcon is an extensible framework, providing the bare minimums. And if you look at it from a performance point of view, it totally makes sense. Not everyone needs translations, and there's no point bloating the base framework with it. If you need a functionality, implement it.
NativeArray translations are designed to service small projects, where the translator is the developer.
DbAdapter is perfect for a site where you write translations using an admin page. The performance is bad, but usage is convenient.
Gettext is kind of an industry standard. There IS is a plethora of tools and transpilers and community sourced translation pages, where you upload the raw .po file and others translate it for you. You do need a tool to extract phrases from the source, but that's why you have tools like msgcat, msgconv msggrep, etc... And it's performance is excellent.
Every adapter provided by Phalcon has it's use case. Ignorance is not an excuse.