Hello there, Mayoite!
After you've transferred the images from your Sony A6000 to your Samsung phone, the images will be stored on the internal memory of the phone, however, I think after you've transferred them, you can easily put the images to the SD Card in the phone by going to Settings and then to Storage.
Once you've tapped on storage, scroll down until you see Miscellaneous. Below miscellaneous, it'll say Transfer data to SD card.
Tap on that, and you can choose what you'd like to transfer to the SD card, such as photos and videos. Once you select what you want to transfer, it'll move all the stuff to your SD card, including the photos from your A6000.
Now, I don't have a Samsung phone. I have a Sony phone, but both run Android, so I'm pretty sure that the Settings thing is the same. 
And if a moderator on this website sees your feedback about the design flaw, I'm sure that they will pass your feeback on to the right department! Have a nice day!
Best regards,