Because you're not buying Helvetica, but a digital variant of it. It's like a performance of classical music. Also Helvetica specifically is from 1957, so it ma

Because you're not buying Helvetica, but a digital variant of it. It's like a performance of classical music. Also Helvetica specifically is from 1957, so it may not in the public domain yet (depending on location). There are actually several variants all named Helvetica, which is why it's a really bad font to put into your CSS font stack if you're not delivering it yourself. Newer variants tend to use other names (e.g. Neue Haas Grotesk).