[Affinity Photo Save/Export Behavior.]

Why can't I save a photo in the same format as the file I originally opened.  For example, If I opened a TIFF file, why isn't it saved/saved as a TIFF file with the same characteristics?  Why am I forced to save as an Affinity Photo file format?  Also, when I export a file, why aren't the default export characteristics specific to the file content/type.  For example, I open a TIFF file and clean up the image.  The Save option is grayed out and Save as converts the file to an afphoto file.  If I export the file to a TIFF file the Preset is blank even though there is a default Preset for every other export format.  Also, I have to choose between Nearest Neighbor, Bilinear, Bicubic, Lanczos 3 (separable) or Lanczos 3 (non-separable) resampling even though I typically choose a TIFF file because I don't want compression.  Is resampling relevant for an uncompressed file?  Even though there is adequate space on the export pop-up, I have to click on the More button to see that I have compression choices for a TIFF export and the default is ZIP.  I would expect the compression default for TIFF to be None.  When I change the compression to None a resampling choice is still required.  This dialog doesn't make sense to me and leaves me concerned about what I will be getting as an export file.  Does this dialog make sense to anyone.  Perhaps you can explain it to me.

Thanks.