The problem is, even if the CPU is 64-Bit maybe the installed OS is only 32-Bit. Of course, this is only a problem if you care about it.
If you are using the non-native stuff - the CPU doesn't care and also if it is 32 or 64 bit.
But I like to debug my stuff, so I need a 64-Bit device and I really dislike spending a lot of money on the kind of device, because my daily drive is an iPhone.
Spending more the 300€ for a device just for some debugging is crazy.
If you google for a 64-Bit Android you do not find anything, because nobody cares about this.
It is also very hard to get the information on what CPU and what version of the OS are running. You have to install AIDA64 or some other test-apps.
So if you have the proof that your device is 64-Bit and also has a 64-bit OS installed and costs less then 250€ please leave a comment.