There are indeed significant differences. The main one is that Sass is, basically, a "code generator". It's a sort of template language that generates CSS code

There are indeed significant differences. The main one is that Sass is, basically, a "code generator". It's a sort of template language that generates CSS code. And so, a "Sass-if" works at code generation time, that is, when you execute the Sass command: sass-if (some logical condition) { <some CSS code> } else { <some other CSS code> } Depending on the condition and at compile time, sass would spit out the first block of code or the second. The condition is, basically, a calculated expression that applies to values and variables available at compile time. Then -after deployment and when a client visits your website- that CSS code is served to the client. Clients are varied and so CSS wants to have its own if structure that applies at runtime. The conditions generally would check the current runtime conditions (i.e. is this running on a large screen? is this browser in vertical orientation? etc) css-if (some condition pertaining this specific current browser) { <some CSS code> } else { <some other CSS code> } So, yes, they are clearly and necessarily different, both in scope and usage. And so you'd generally need both if because they do different things. And that where the problem arises, because if you want to have both, their syntaxes need to be distinguishable.