Downwards Triangle-Headed Arrow

No, it is a separate character with the same meaning.

The familiar down arrow is ↓. ⭣ points the same way but has a filled triangle head, which in many fonts looks bolder in headings, bullet lists and labels like "Download ⭣" or "Details ⭣". Readers take both the same way.

Because they are different characters, a search for ↓ usually won't match ⭣, and a document that mixes them can look uneven.

Why can it be hard to type and see?

No standard keyboard layout types it, and some fonts lack it.

⭣ joined Unicode in 2014, much later than ↓, so a device or app whose fonts don't include it shows an empty box instead. A broader font can fix that; if your reader might not see it, the older ↓ is likely the safer choice.