URLs can change, so in order to keep a consistent record, marketo uses the ID instead. The ID is basically marketo's way of recognizing the page.
The same is done with leads. You can modify a lead but their ID won't change.
That way you will be able to have consistent analytics regardless of what small changes you may make.
I understand the value of Marketo using IDs on records, but they are not usable by the Marketo user.
The Visit Web Page Activity Detail record shows both the Webpage ID and the Webpage URL. Also, the Visited Web Page and Visits Web Page filter and trigger use the Webpage URL as a constraint, not the Webpage ID.
However, the Click Link and Fill Out Form Activity Detail records do not display the Webpage URL, even though it is avalable and is displayed in the Detail column of the Activity Log for Click Link activities. Also, the Clicked Link on Web Page, Clicks Link on Web Page, Fills Out Form and Filled Out Form filters and triggers all use the Webpage URL as a constraint, not the Webpage ID.
Is this a purposeful omission or an oversight? Should I submit an Idea for this?
Honestly, it's an internal implementation we probably should have hidden away better. What we show in the Activity Log when you double click is basically what lives in our database- I'd generally want to clean this up but it hasn't been something we've wanted to priotize over other new features.
You could submit an idea to change what shows up in the UI here. I think most folks generally run Smart Lists to access this data rather than clicking on the individual Activities so it hasnt' come up much in the past.