Manual or Power Recline
A manual recliner opens on a side handle with no cord and nothing to wire in. A power recliner uses an electric motor controlled at a button, trading that simplicity for stepless position control and a cord that has to reach an outlet.
What the handle gives up
A manual mechanism has two or three fixed positions - upright, part-reclined, fully reclined - set by where the linkage locks. Getting a position between those points usually means holding the handle partway, which is not a stable rest. It asks nothing of the room in return: no cord, no outlet, nothing to fail electrically over the life of the chair.
What the motor buys
A power mechanism can stop anywhere between upright and fully reclined, held there by the motor rather than a mechanical catch. That continuous range is the entire case for paying more and needing a cord. It also removes the physical effort of the handle, which matters more for some people than others.
What the motor costs, beyond price
The chair needs to stand somewhere a cord can reach an outlet, which constrains room layout in a way a manual chair never does. It also adds a component that can fail - a motor, a switch, a wiring harness - where a manual handle has one moving linkage and nothing electric. Neither of those is a reason to avoid power recline; they are the terms of the trade, and power and USB ports covers what the outlet itself needs to supply.
Where massage and heat fit in
Massage and lumbar heat are not tied to which recline mechanism a chair uses - this range includes a manual chair with both features, where the recline is a handle and only the comfort features draw power. That is worth knowing before assuming "powered features" means "power recline."
Questions
Is power recline more reliable than manual?
No - the reverse, generally. A manual handle has one mechanical linkage and nothing electric to fail. A motor, switch and wiring are extra components that can go wrong over years of use, in exchange for stepless positioning.
Can a manual recliner have massage or heat?
Yes. Massage and heat are powered separately from the recline mechanism itself, so a chair can have a manual handle and still need an outlet for those features.
Does power recline need a special outlet?
No, a standard household outlet within reach of the cord is normally enough - see power and USB ports.
Which is better for someone with limited grip strength?
Power recline removes the physical effort of operating a handle, which is usually the deciding factor in that situation.