It is a trade-off - here's the seat guru review of the same seat, opposite side of the cabin:
Don't make the mistake of booking this seat. SQ charges the outrageous price of $88.50AUD but I booked it thinking it was as described, an extra legroom seat. After I read the other comments on Seat Guru I realised with a fixed armrest, two people to your left, slightly narrower seat, 47K legs intruding onto you on an overnight flight, a bulkhead above which restricts mobility, no power charging in the seat, tv arm digging in to your thigh why are Singapore airlines even charging for this seat, let alone the price of $88.50AUD. I am going to try and get my money refunded for this seat, I think it is wrong to describe the seat in such a way without also mentioning its deficiencies.
Narrow seats and the entertainment unit are highlighted for row 41, which is the same sort of set up with the fixed armrests:
41 A & B are already narrow due to dinner table in the armrest, however they are even narrower due to the entertainment handset being located inside o of the seat, and therefore protrudes out into the seat width making an already narrow seat, super narrow - VERY UNCOMFORTABLE. This configuration follows seats 41 A & B. This is a big design fail.
The advantage of the comfort seat is that with ~25.5 inches of seat width per person you can move around, get comfortable, use the space of the middle seat for legroom.