CDs are used for storage but executable files can be ran from them - all you programs are loaded via the CD/DVD. Yes, all files burned to CD become read only and if you copy any back to your hard drive you will need to change the name if you intend to modify the file. I know nothing about re-writable CDs but I would suggest you erase everything when wiping it. Do not apologise for asking seemingly basic questions, asking is learning.

Yeah, the spindle idea would work fine until you start to search for a specific CD or DVD and keep pulling ones out, and keep pulling, and keep pulling--and then realize the one you want is 3 from the bottom! That would SO annoy me! Binders are a good idea, as are some of the specially sized boxes that places like the Container Store and Target sell for storage of CDs and DVDs. I think they usually come with individual sleeves so that nothing gets scratched, but all in all I think they save space. Plus you could insert index dividers to separate jazz from hard rock. A friend of mine (young) decided to burn all her CDs (and she had a lot) to her computer, backed them up on an external hard drive, and then sold the CDs to a music store. I'm not sure I'm cool with that idea yet--I always think even my external back-up will fail.

I purchased a CD case (tall and narrow, made out of wood) from Ikea. It's really nice, but you do see the DVDs. I like the fact that it is very narrow so you don't notice it as much. I don't think I paid over $75.00 for it. If you don't have Ikea by you I believe they have a catalog that you can order from. If you really don't like to look at them you should purchase a closed cabinet. Ikea also has those. Here is a link that might be useful: Christy's Thrifty Decorating

Yes streaming apps is not their focus. On the 203 they included a 4k HDMI input so you can stream your Roku/Apple TV, Firestick etc through the player and not lose an HDMI input on your TV. The used to have the 103 and 105 priced similarly when they came out with these blu-ray players. If you assume a 2017 version of a similar feature upgrade from the 203 to the 205, then they are probably something like this: https://www.oppodigital.com/KnowledgeBase.aspx?KBID=37&ProdID=BDP-93 In the 103 /105 case, the higher end version was based mostly on improving the audio listening experience.