Whereas in the US, if you get 25,000 signatures on a petition, you get... a polite response summarizing the talking points you already knew, and explaining why nothing will change.

That is, if you're lucky - I believe we're still waiting on the promised response to this one: https://wwws.whitehouse.gov/petitions#%21/petition/actually-...

It doesn't have to be seriously debated - it just has to be officially mentioned, it's still just democracy window dressing.

It doesn't have to be debated at all - if a petition reaches the threshold then the committee just 'consider' it for a debate.

There was a petition to abandon the recent NHS reforms that reached the threshold and wasn't put forward for debate.

Okay, so it's not really any better than the US system.

Incidentally, in the 24 hours after I posted that, they did in fact finally release a response to that petition. It was long after the deadline that they promise for petitions that reach the threshold, and it wasn't much more than a justification of what they already do, but at this point I doubt anybody was expecting anything more.