If you exclude 'emojis' which are literally just picture forms of characters in existing languages:

Technically, they're pictoglyphs, not hieroglyphs.

Emojis represent the literal thing they portray (pictogram), the word associated with that literal thing (logogram), and, to varying degrees to different people, represent other related concepts and associated ideas (ideogram).

Hieroglyphs do all of that, but additionally also represent spoken syllables and alphabetic characters, and follow a concrete syntax amd grammar system that allows for a much more extensive vocabulary, as well as more complex sentence structures than emojis, which have far more certain and unambiguous meanings.

As an example of that, try to represent my previous sentence using only emojis, and then present that string of emojis to a random person you know and ask them what it means.

Basically, hieroglyphs constitute an actual language, purely using emojis is playing pictionary as a means of communication.

The house question traveled back in time, damn

Home you?

19:00 somewhat ruined the illusion, bringing those modern Arabic numerals into the mix.

There's a perfectly good "at sunset" hieroglyphic 🌄

(it's technically sunrise, but okay)

🗿

This is needlessly complicated. All I need is a beer emoji and I would be at the guys house with a six pack in 15 minutes.

Give it a couple millennia and they will evolve back into alphabets and syllabaries