If you have a club foot, you cannot run. Adversely conditioned planets, even when weak, can impose similar constraints. And in that way can be seen as strong.
I have known and observed many people with a very high intelligence who were unable to access and utilize that intelligence due to other personality traits, for example.
A specific example offered for discussion might be fruitful.
Debilitated planets are not exalted. The Olde astrologers were meticulous in their choice of words used to describe the conditions of the planets.
To exalt is to "raise on high". It elevates in position and power. It enhances activity and intensifies. It brings glory. The sign opposing the sign of exaltation (of a planet) is said to be its fall. It signifies going from bad to worse, to suffer ruin, defeat or failure.
There are many sorts of debility: fall, exile, peregrination...and each has its characteristics, although for general purposes "debilitated" will tell what we need to know.