Hello! Welcome to our forum!
There are many reasons for this. The US has an easily accessible dataset of VFR sectionals that are public domain and free to use. In Europe, the situation is completely different as you can imagine 
Adding just one European country is as big (if not bigger) of an undertaking as adding the whole of the US and will only benefit a select few of our users, so this is not a high priority for us. You can read the official statement from our CTO here:
Since we closed this topic in favor of the one mentioned above, I will now close this one as well. Feel free to engage with the one above and leave your vote!
Kind Regards,
Malte