Mogrify works better to convert TIFF to PNG or use 'convert' one at a time with a for loop

Pontifications

Following on from yesterday’s How to convert all TIFFs to PNGs in a separate sub directory using ImageMagick / GraphicsMagick, actually mogrify or convert one at a time in a for loop works better! A bug in batch convert perhaps?!?
example:

# Warning mogrify will overwrite your files if you don't 
# change format or do something to create new filenames
# or put the files in a subdirectory
gm mogrify -format png *.TIF 