X-Men Dark Phoenix 3D Blu Ray 2019

Takes a lot of time to extract left and right eyes, then encode an MVC compliant 3D Blu-ray, it’s not worth it a lot of the time when the source is a web-dl as you’re just blowing up the file size with increased bitrate, not increasing the quality.
Sometimes ill do it if the source web-dl is high enough bitrate to benefit from the ISO version. Sometimes I will use a high quality web-dl over blu-ray if it is open matte and will benefit from the extra aspect ratio, which makes the 3D more immersive.
Dark Phoenix is blu-ray source, I just wanted to get the HOU and FSBS versions out first because I had to jump in and get started on the new Dungeons and Dragons movie ASAP. ISO might come later, I’m very busy with other conversions, but I kept the 3D master file (98gb) of this so I can put out an ISO at some point.

Fantastic Four was from a blu-ray source. Hancock was open matte, thats why i used that version, it had more screen space compared to the blu-ray. When I dont use open matte, some users stretch the image to fill the screen, as well as letterbox formats generally not translating as well to 3D as 16:9.
Its about creating the best 3D experience, having your entire screen taken up by the film provides more immersion, so using open matte is the best option. Dark Phoenix is blu-ray too.
I use blu-ray 80-90% of the time, with some new releases, WEB-DL is all that is available at the time and I use the version with the highest bitrate available.

But overall it’s usually because of aspect ratio or because the film just came out on digital.
Some blu-rays also have slight differences with variable frame rate and converting them can be tricky without changing the frame rate.
WEB-DL is almost always constant.

Disagree with your comment about them being almost DVD quality, they are all 1080 sources, though Hancock was lower overall due to open matte being lower bitrate.
Are you using the ISO of these releases? Because there are many projector users that have no issues with quality.