You should use the features provided by your browser and OS for inserting special characters. For example, on Chrome on Mac OS, you can right-click and select "Emoji & Symbols".
Draftail is not a programmer-facing tool: it's a tool for writers, and it wouldn't make sense for it to interpret the entered text as HTML code, any more than it would make sense for Google Docs or Microsoft Word to do the same.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…