Content that allows users to make quicker decisions can reduce wasted energy and time on-site.
Yes, you want to engage and retain your users, but not with content that's unclear or requires a degree to decipher.
Both SEO and onsite search features will reduce time wasted by users on your site. They are there with a goal in mind and it's our job to get them there as easily as possible.
Reviewing and removing content that is no longer relevant will reduce energy consumption and storage. Not everyone needs to see those seven year old christmas party pics, it's okay to take them down. Let them go Janet, LET THEM GO.