Chocolate is the easy answer. The more chocolate you eat and padding you add between you and the seat, the less you will need suspension, though to the other extreme, the more your trike frame will appreciate suspension.
For some, including me, suspension can mean the difference between riding and not. For those with back and or neck problems where vibrations can cause discomfort or real pain. Rear suspension is a great start to a resolution while full suspension (front and rear) is pretty good.
Some people don't understand the need for complexity on what is essentially a "push-bike" and complexity always has costs of some sort. There are a large number of recumbent trikes around and you can easily select a model that fits your needs or beliefs. Suspension is not compulsory for most but it is helpful to a good few.
As with recumbents that are not mass produced, the price of additions also tends to be higher than what you can get on cycle from Big W. The question is - does the result justify the inclusion. For me, no suspension means no riding, no riding means no exercise, no exercise leads to things like social exclusion, physical deterioration and all that can lead to like diabetes, stroke and alike. Some times it is more important to find a way to get a situation workable for you, so when it comes to this area the only person you need to listen to is you.
Try the difference:
Look at the price tag
Sit on the seat
Go for a ride
Lift it off the ground if you need to put it in the car regularly
See how easily it folds and what work is involved with that action
Deos the rear wheel fold flat without having to remove it
Can you have quick release (QR) wheels if you need to get it into a smaller space
Does the braking system (Disk/Drum) prevent QR
What seat sizes are available and do they adjust suitably