They promise to get you there sometime. Full stop.

They never accept consequential damages - missed cruise ships, meetings, weddings, ticket scalping deadlines, etc. Never.

The best way to understand air travel is to know there are often delays - weather, occasional breakdowns, crews running out of permissible air time at the month's end, Air Traffic Control ground holds, airport congestion, etc. etc. and therefore build in plenty of "buffer" time, plus be as knowledgeable as possible so you can have input into the results and not be a hapless victim of circumstances.

Fortunately, reading FlyerTalk can help one learn valuable information and coping kills.

E.g. On a BA ticket to Venice for a cruise, our connection at DFW was obviously not going to work out due to a significantly delayed arriving flight and no available seats onward from LHR (or even LGW) to VCE for two days, causing us to miss our cruise departure and lose nonrefundable hotel arrangements. (EC compensation wouldn't have been much help in these circumstances.)

I researched using available tools and found alternate flights, told a BA agent what the consequences were to us because of the delay and requested BA endorse my ticket to LH (Lufthansa) and flew DFW-FRA-VCE, arriving close to our originally scheduled time.