I've taken to doing a similar thing except on my phone and anywhere with limited storage I use different things instead of MP3 because that is an ancient technology. I have the lossless copy on my big storage. And on my phone I have xHE-AAC copies of pretty much my entire library. I figure since everything I listen to on my phone goes through compression anyway even through the highest quality ldac that my nice headset has and especially because the vehicles I drive in have crappy Bluetooth audio that using this way more efficient codec is a pretty good trade-off.