Sounds like it's working for you; you also seem to have more technical expertise than is available in many dealer groups. I've met with quite literally hundreds of dealers and most do not have the staff on-hand to do things like that. They may be in their analytics every day, but they don't usually have the skills to diagnose or debug a JS issue. But sounds likes your group does, which is great!
But even with your example, if the vendor decides one day to start using the .phone CSS class instead of .phone_number, then your script breaks. That's just the fragile nature of scripts that are effectively tied to the DOM.
I'd still argue that it's rapidly becoming unnecessary, or even undesirable, to roll your own solutions for things that the larger community is now agreeing to bake into their products. Just makes reporting and analytics so much easier, and more powerful, when everyone is using the same standard.
Your experience is vastly better than mine has been. 
Not knocking the vendors, but their support staff are usually overworked & understaffed and even getting simple changes can sometimes take forever.
If you aren't able to get the docs you want for ASC, let me know and I can send them over to you.
