Back in 2015, automated translations were nothing like they are now, and text translated by these tools alone, with no human intervention, often rendered a poor result, which may have been both unintelligible, and misleading with regards to the original content intent.
Fast forwarding to end of 2020, I personally find Google Translate to be pretty accurate (with obvious counter-examples we can all easily draw up), to the point that it is likely better than an average person who wants to translate a text, and possibly not up to the standards of a professional translator (although they may find aid in such tools as an initial baseline).
It depends on the languages that are translated, most translations look decidedly better than five years ago, especially from English and into English when major European languages are involved, but the mistranslations when they appear, and appear they will, can still be jarring, the more 'exotic' a language from an Anglophone perspective, the worse it gets.