Created blu-ray disk image, burned to disc with Apple Superdrive, won't play in dvd player. What to do?

Sorry, but I'm having trouble with your first sentence, "The rest of the topic is technical..."

I was only trying to fit two items of yours together. The now edited link, and your comment; This is a submission. I have a feeling they don't like submissions much.

The latter seemed to me to be asking if it's okay to ask for a purchasing selection of a Blu-ray or DVD player/drive, and wondering if that may also get edited out as "not a Mac question".

That's all. Nothing to be even slightly concerned about.

MacGo Blu-ray Player Pro. Purchase optional. Open ended evalution with regular updates — provided you can live with subtle watermark in upper left corner of player until purchased. Don't expect to turn an Apple Superdrive into a Blu-ray device.

If FCPX kicks out a standard BDMV folder, then burning it to a DVD will result in a disk that doesn't work. A BDMV folder needs to be on a Blu-ray disk, which of course cannot be read by a DVD drive or set-top player.

Your choices are to purchase an external Blu-ray drive so you can play back your created disks (you'll still need something like MacGo Blu-Ray Player to view it). Play back the BDMV folder directly (again, with something like MacGo Blu-Ray Player). Or, redo the output formatted for a VIDEO_TS folder that can be properly burned to a DVD that works. The downside is a DVD is always the previous, low resolution standard TV format.

The totally free "Leawo Blu-ray Player" I posted above seems to work just fine. Played my blu-ray-disc-image-burnt-to-regular-dvd no problem.

Probably because it doesn't really care what type of disk it's on. I just looks for the H.264 (.mp4) video and plays it.

Yes, you can put Blu-ray on a DVD. It's specifically known as a High Definition DVD. Since a single layer DVD can only hold about 4.2 GB of data, the video can't be very long. A regular DVD computer drive or TV set top player still won't know what to do with it since it can't read or decode that format. But a Blu-ray drive can.

The rest of the topic is technical, so I sure wouldn't worry about simply asking about a source device.

DVD and Blu-ray are both very common. Pretty much any movie or TV series is released on both. The nice thing about a Blu-ray drive is it will play either type of disk. Less common is the newer 4K Blu-ray format. I don't know if that will ever catch on at any high level of use.

You had first said you couldn't play it, then followed up with a link. Without an explanation, such as, "I found software that worked to play it.", the link alone probably seemed like advertising. We see a fair amount of that here. A new user will ask all kinds of lame questions, then uses another account to answer themselves and add a link to software they're selling that just happens to be a solution to the every question posted under the first account.