Cookieless and accuracy: Pros and Cons

General questions
1

Hello,
I am new to Matomo and I really like it so far.

I’ve set up a cookieless solution (disableCookies) and I would like to understand more precisely pros and cons related to accuracy, in particular for small websites.

As far as I have understood, in a cookieless environment matomo detects users using browser, IP and other “signals”.

My questions are:

  1. Obviously there could be two users having the same signals and in this case the recognition wouldn’t be accurate but how often this happens (more or less)? There is a FAQ about this
    https://matomo.org/faq/general/faq_156/
    but it doesn’t give detailed information. In particular, for small websites I guess it is less frequent to have two different users with same cookieless fingerprint.

The reason I ask this is because I know that I loose accuracy on one side, but on the other side if I use cookies I need to ask cookie consent and I would loose a lot of information just because there are people who will not consent the cookie (so there is a kind of trade-off between the two)

  1. If the cookie is not allowed by the user, does matomo automatically move to the cookieless solution for that visit? I didn’t find this info.

  2. This page:
    https://matomo.org/faq/general/faq_156/
    says that:

Goals and Ecommerce conversions will be attributed to the channel used in the visit that converts

I don’t understand why: if the user returns and provides the same fingerprint, why the visits are not linked to the same user?

Thanks!