The process by which SSL certificates are issued by Certificate Authorities (CA) involves checking a company's identity. In addition, several CA's check additional details like photo-ID, letter of  company formation and even commercial directories to ensure that the person requesting a SSL certificate indeed is a part of the organization he is purchasing the certificate for.

The benefits of SSL certificates therefore are two-fold:

SSL certificates or site seals effectively are letting a website's visitors and potential customers know that the site has been approved by leading Certificate Authorities, and hence are almost certainly genuine businesses. For commercial sites this often leads to greater number of visits leading to sales, fewer customers abandoning their shopping carts before paying, therefore resulting in more sales.
SSL encryption stops personal or sensitive data from traveling across networks in full public view. Anyone can intercept non-secure data including sensitive financial data, if not encrypted, and use it for personal gains or even modify it. Customers visiting SSL sites know that their data is safe from the point of view of transmission, and any security leak at the server's end is not their problem.
For banks, public and governmental organizations, SSL certification is mandatory as the loss or theft of data can lead to a serious collapse of pubic confidence. In addition, identity theft with government data is a serious security risk. Malicious hackers often specifically target prime financial and government institutions for testing their 'hacking skills'. In addition, a lot of 'phishers' try to lead legitimate customers away from these sites and obtain sensitive information. To avoid these disasters, SSL certificates which use extremely strong encryption algorithms may be used for these sensitive websites. Internet banking and operating accounts from home, be it your own or your client's, is only made possible because of SSL.

Most commercial SSL Certificate Authorities also provide hundreds of thousands worth of dollars of warranty to cover losses in the unlikely event of security lapse despite SSL. This is an additional layer of insurance that SSL certificates bring with them.

Current SSL protocols have significantly reduced the chances of traditional forms of hacking – including identity theft, garbling attacks (where an attacker garbles messages hoping to receive confusing information), replaying messages, cut and paste attacks (where intruding person intercepts a deciphered code and cuts and pastes it to gain access), cipher-suite rollback attacks and version rollback attacks (both of which attempt to revert the encryption level to a lower, less secure version), dictionary attacks (where the attacker tries to decipher the code) and short block attacks (where messages with short test sequences followed by a lot of padding are easily decrypted). Current SSL protocols are sophisticated enough to prevent all known forms of hacking, and the chances of security breaches are astonishingly small.