Server logs are easily faked. There's a lot of mistrust in the industry (well-earned, due to many scams in the past). Third-party web analytics providers, implemented via plain-text JavaScript anybody can audit, are fair.
(That ignores of course that server logs are virtually useless for determining a user's behavior on a single page app. It's not the ONLY reason server logs aren't used, but perhaps is the most important reason.)
(That ignores of course that server logs are virtually useless for determining a user's behavior on a single page app. It's not the ONLY reason server logs aren't used, but perhaps is the most important reason.)