Obviously, I wholly agree with your preference for moral and values based justifications.
But I also acknowledge ROI does help fend off alternate agendas. My state's investments in birdwatching, vineyards, hunting/fishing/gaming. etc have huge ROI. Thereby empowering the conservationsists in those never ending policymaking slap fights.
Adjacently, I've seen (local) budgets for pre-K get over the hump because of their outsized economic impact. Some people only see the world thru dollars signs.
Framing with positive ROI helps moot the "we can't afford it" zero sum scarcity mindset. Like exposing NIMBYs.
Based on the ROI, we can't afford TO NOT invest in our national parks. Taking away the economic counter arguments shows the opponents just don't want to. For reasons.