This appears to be new in 25.10 (which is also my first install version), so there’s limited information I can find about it. Bouncing around ChatGPT for random help along the way, it has consistently recommended I use this Purpose for my photos, but I can’t really find any outside information to validate (or contradict) it..
My photo library is ~5TB and growing, and is a bunch of 50MB+ RAW photos, along with maybe half of them having sidecar XMP/ACR files which are generally <1MB and almost always <500KB.
I am using Mac OS as my primary computer, but in the recent past was using Windows. There’s also the warning about switching it with existing data, I believe related to the Apple-style character encoding. I believe this shouldn’t really be a concern for me, as all my file and folder names are very simple and consistent? A bunch of name_filenumber.cr2, and similar… I can’t think of any other special characters that might have been used (I guess Final Cut probably does with a bunch of autogenerated temp files or something?). My Lightroom catalog also creates a bunch of cache files, BUT THIS IS ON A LOCAL NVME, NOT THE SMB SHARE.