In terms of RHD, I don't need one to get into the drivers seat, I've always used the steering wheel. UNLESS getting in is tight (door not all the way open for example), then the pillar grab handle is very handy. The one up top will do the job, just not as well.
A grab handle on the pillar for the passengers is however very much generally required on a vehicle this tall, and luckily it's supplied in the RHD.
I found getting into the back seats a bit of a PITA without grab handles though, and this is where I reckon getting them retrofitted would be worth it if you had people getting in and out of the back all the time..
Yes, you can use the door, or the top handles, or the body frame, or the seat or the roof rails or whatever at a pinch, but for the extra $30 it would have cost to install handles in the rear to give a much better entry, it would have been worth it.