I feel that having that validation of compliance shows that the coding for a site is accurately and efficiently organized. One way I was taught when learning how to program was if you design a program or website for a company and then you leave that company, how easy will the next person be able to interpret the code and make changes if necessary.
Good point ..
But there are for example some java script codes not accepted by the w3c validation .. what do you do about that ..
Don't tell me about it . .