I can see sidehammer, hammer and trapper bots abusig the 140cm square extender due to its weight to lenght ratio.
That's what you would think, but a lot of times you want something shorter than 140cm, and that extender only comes in one size. I've found that there's actually very few applications where it's really useful. Hammer bots is one, and ultralong wedges is another. But in both cases you can just as effectively use shorter, regular extenders.
And I haven't tried it, but I'm sure it would be useful for Flying Guillotine-type bots as well...
