Out of curiosity I enabled DNSSEC checking beginning this year. I mostly noted nothing in my browsing. However, with 2 services I noted obscure problems that worked only partially. Some Jira plugins and Swedish railway SJ. I needed to excempt some of their domains from being checked to use their services. Of course you waste a couple of hours every time it happens because you don't think of DNSEC first when some web-based services behaves weirdly. There might be more requests not served to my browser, but I just never noticed or bothered to debug.
So not fit for general use. And even as an experienced developer it's not easy to understand why an exception would be needed. A bug in systemd? Incorrect data in DNS? A real attack?
Edit: I don't use standard DNS on port 53 at all. Blocked outgoing requests on that port. Everything DoH or DoT. Of course I need to trust those endpoints at least in repect to confidentiality. And most domains are unsigned. At least for those unsigned ones I need to just trust also in respect to integrity.
Give SJ the option to turn off DNSSEC and their website will stay broken. Give people a "someone might be tampering with your connection" popup and they would start caring.
There are also other issues with DNSSEC that need working out, but I still believe it does much more good than it does bad. Leaving everything in the background with an easy-to-disable setting makes it next to useless.
Full ACK. As a part of this, DNSsec validation needs to be as close to the client app as possible and reasonable; definitely never off-host. (Caches can do additional validation, but that makes the error reporting complicated.)
corollary: the AD bit should never be relied on on anything actually on the network. Maybe on localhost, but even there it's questionable in UX results.