It would be interesting if you could come up with those other reasons, if there are any. To my knowledge, Alamy is the only one that people ever mention.
Another one is Smug Mug... for whatever reason they don't seem to fully index beyond a certain number of keywords (I've just discovered this in trying to base a smart collection on keywords). Some of my images would not be recognized for the keyword. The only difference I can see thusfar is that those images have more keywords. Granted I'm still looking into this one.
Another is just the way Lightroom sorts in the keyword list (which is slight different but still alphabetical). There are some parts of the hierarchy I would like to keyword first, second, etc. Sure I can use underscore, asterick, etc. to make it work but why not just let it be user ordered.
In my mind, I would think Lightroom could write the keywords just as they are laid out in the hierarchy and in that order. Maybe that's more difficult than it seems.
Couldn't agree more. Look up my Big Note plug-in which you can expand if you're (slightly) technically-minded. But this shouldn't be left to plug-ins - no other serious photo cataloguing program lacks custom fields.
I do use your Big Note plug-in. The field size is limited however. I'm familiar with some programming, I've used VB and SQL a lot (almost every day). I've looked at the code and I can't determine how to set the field type and/or size property. I've looked into it a little but the answer didn't come up quickly. If I could figure that out it would be perfect for my needs. As you said however, why have to use a plug-in for that purpose? There are many other fields that would be great to use as well (film type, lens, etc.) for film photography information. Currently I use analog exif or exif tool for that, but it's a separate step in the workflow. If you would be willing to give me a clue how to change the field size (amount that can be stored) I'd be eternally grateful