Here's why:
* Past participles are used to form perfect tenses (e.g., present perfect, past perfect) and passive voice constructions.
Examples:
* Present perfect: "He has considered all the options."
* Past perfect: "She had considered the proposal before making a decision."
* Passive voice: "The plan was considered carefully."
While "considered" can be used as a verb, it's more commonly used as a past participle in these grammatical contexts.