… but I can’t work out what it’s for

Did the reviewer simply not get the memo, or what?

The G Line is specifically designed to be off-road oriented, with much larger wheels than what Brompton’s usually come with.

It’s for people who want a super-compact gravel bike. It quite literally makes off road riding on a Brompton possible, since it’s hardly practical to do with the standard 16" wheels and frame of other Brompton bikes.

Is it a worse folding bike? Hardly, when you consider the competition! Is it as compact as other Brompton bikes? No. But is still far more compact than other folding bikes, and certainly tiny compared to even the smallest traditional gravel bike.

It’s a really nice addition to their lineup. I’d be interested to see if they come up with 20" commuter bikes now.

This seems like a great option for people commuting to Smurf Village every day