Badboy; Of course you're right - an electronic logbook can not suit every pilots needs. However - a great number of pilots like to use them for easy logging, automatic summaries etc. as well as for "useless-but-fun" statistics. Unlike Excel, myWebLog can also be accessed from any computer with internet access (I'm really not trying to advertise here).
Excel can do almost everything the other logbooks can, but why invent the wheel again? Most of the software out there are ready to use or easily reconfigurable to fit your needs. If there is something you want to add/change you can always write an email to the developer/s. In most cases they'll listen to you!
Blue skies!
Best regards,
Magnus Winsth / myWebLog