I would say it takes you to about a B2 Level, which is a very solid base for pushing on.
Of course, you'll only reach B2 if you use the language in situations (e.g. reading news articles, watching movies and -most importantly- speaking).
If the only time you are using your target language is when you're using Lingvist, then you won't exceed A1-A2.
It's like programming: if all you do is watch online courses but don't practice on your own, then you'll have theoretical knowledge but no practical experience.
In conclusion, you should NEVER use any app or learning material exclusively. Lingvist will give you a good start but you MUST supplement it with daily life situations if you want to reach a "proper" CEFR level.