There is a point, actually several points to use an Ethernet shield.
If you are using existing libraries that rely on the Ethernet library, e.g, ArdOSC or DHCP/Bonjour you save yourself a lot of time coding things that are already coded. Good luck trying to code that functionality in HTML & javascript 
I understand that the motivations of people for engaging in Arduino projects is different. Perhaps if you consider it a learnig experience and time for coding is not a problem, in that case elimiating the Ethernet card and library and associated functionality a a valid approach.
However, if one intends to get a project on their feet quickly and has a specific functionality in mind, then spending $30 on a little extra hardware is not an issue.