1km is actually walking distance from Cube8 to Novena MRT station, and very direct also because just walk out of Cube8 and walk along Thomson Road straight and he/she will hit Novena MRT station, no need to climb overhead bridges or turn left and right and left and right etc. To some people, they can still walk so they buy Cube8. To me I can't so I don't buy there.
On the other hand, Carabelle is more than 1km in radius from Clementi MRT station. To actually walk to Clementi MRT station I also don't know how, may be walk along West Coast road, then turn left, then turn right, then turn left, walk along AYE, cross overhead bridge, turn left into Clementi then turn right then turn left ....(blah blah blah) - I got lost already. Actual walking distance including climbing overhead bridges may be 2km? If 1km is not walkable, 2km is like living in the mountain and cannot walk out?
Just to walk out to take a bus from Carabelle also have to walk so far away. Cube8 residents just need to walk out of their estate and there is already a bus stop beside there, just take almost any bus and they can arrive at Novena MRT station about 2 bus stops away. Try taking a public bus from Carabelle to Clementi MRT station? Before that, have to walk and turn left and right and left? Alight from bus still have to walk left and right and left...?