What you are sharing is simply not true and I will clarify. A cookie banner is required when you store PII data. This is personal identifiable information. This includes, but is not limited to an IP address, a cookie with an user identifier, ... You are free to collect data that is not part of this without a cookie banner. You are also referring to a URL as being device information, this is not device information but basically a page view. You are allowed to collect page views and URLs that a linked to this page views with a cookie banner.
You are describing retention for your business. That's only possible with a cookie banner. It makes perfect sense because you need to calculate retention somehow. If you can calculate retention and conversions you are tracking a user. So you need a cookie banner.
Cookie banners are also a thing that are implemented on the web in many wrong ways. You should always have a way to disable cookies. Just a "accept all cookies" is legally invalid under the GDPR. The e-Privacy was already in place before the GDPR and the GDPR is somewhat a clarification of it.
Simple Analytics does not use cookies and does not require a cookie banner. We don't track your visitors and don't calculate retention or conversions. If your service does this, they a tracking your user and you might need a cookie banner.
The ePrivacy is just a _directive_ and doesn't oblige to anything. It's the local laws of Europe that do. We have compiled a detailed list of all the European countries and the respective laws that require an analytics service for opt-in or opt-out style banner. [2]
Retention is not possible without cookies or localStorage, but you can measure retention without storing or processing any PII information.
[1] https://volument.com [2] https://volument.com/learn/data-privacy
How is that defined? For many businesses it is essential to know conversion rates and which users buy, especially if they invest in ads so they can calculate their ROI and know if their campaigns bring in profit or loss, which I think it's pretty "essential".
The law doesn't say anything about it, though: this is just the interpretation and how courts have been treating it, so I wouldn't try to find loopholes around the word "essential" if you intent to follow it.
A court has ruled that tracking cookies used by ad networks, analytics and retargeting require consent [1].
Nothing stopping you from analysing your logged-user data, though (as long as you disclose it to your customers and comply with the rest of GDPR), so it's possible to have those kinds of measurements even without those stupid cookie banners.
[1] https://techcrunch.com/2019/10/01/europes-top-court-says-act...
[1] https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CEL...
Your citation does not mention URLs or clarify why they might be non-essential.
If you're using it to display a page (say: React Router), then it's essential functionality.
If you're using the URL to propagate a unique hash between pages that is used to identify the user for marketing purposes, then it requires consent.
If you don't trust my word on this you might want to check out the official stance of the European Data Protection Board on this (from 2019): https://edpb.europa.eu/sites/edpb/files/files/file1/201905_e...
The EU is working on an ePrivacy regulation btw, which will indeed replace the ePrivacy directive, but it's not likely that it will be passed before 2021 or 2022.
In what country? There is certainly no US law to my knowledge, that says that.
You definitely need a "cookie banner" when using Simple Analytics, Fathom, or Plausible. Any service that accesses the device information such as the URL needs a permission from the user according the ePrivacy directive.
We have consulted EU law specialists when building our upcoming analytics service that is as privacy-friendly as Simple Analytics, while still measuring important things like retention and conversions. More information:
https://volument.com/learn/data-privacy