The phrase "vanity project" refers to a personal endeavor or task someone pursues solely to boost their own image or ego, rather than for practical reasons or benefit to others. Full definition
While local government services and benefits are being cut to the bone, when it comes to funding these kinds of vanity projects, money always appears to be of no object. (politics.co.uk)
Stop blowing money on vanity projects and make sure that basic education is adequately funded. (schoolsweek.co.uk)
Are we journalists or writers or are most of us engaged in vanity projects? (legalblogwatch.typepad.com)