Thanks to the powerful TZX format, it is possible to store a program in its original form, without taking too much space.
When a game is archived in this TZX format, it's finished and it will no longer be necessary to look out for better versions (there can't be).
Because not all platforms have emulators that support TZX files (or don't have one that allows flashloading), we always keep a non-TZX version along with a TZX image. We strive for TAP files that are as close to the original as possible (just the custom loader taken out), but Z80 files are kept in the cases that no TAP file is available yet.