From an SEO / usability perspective does it matter if my site index uses the "all" argument which seems to break the visual hierarchy in the URI?

taxonomy/term/all
taxonomy/term/term1
taxonomy/term/term2

I'm just wondering whether the "all" argument at the end of the URL is a bad practice as far as SEO goes since IMHO if you remove "term1" from the URL you should get "all" however you'd have to replace term1 with "all" to actually get a list of everything...

Does it matter whether it's term/ or term/all?

Thanks,
Chris