And here's why this guy is on my radar: anyone who wants to build a Vampire deck. If you want to build White/Black Vampires in Standard, you want four of these. If you're build some janky Vampire Lords Tribal deck in Modern, you want four. If you're just someone who just wants to build a kitchen table Vampire deck, you want four of these. If you're building a White/Black/X Vampire Commander deck, you want one.
Also, this guy was so popular when he was spoiled that during preorders, the Lieutenant's price spiked to $2.50. It eventually settled to about $0.75 and has been ticking upwards ever since. Ordinarily, I wouldn't get that excited about an uncommon, but he's unique in that he's a two-drop Lord for a very popular Tribe. Being $2-3 in a short time isn't impossible.
I'm not super high on the Legion Lieutenant foils right now, though. Most of the demand for those happened during preorders, as they shot up to $15 for a bit. That isn't to say you shouldn't buy one for your Commander deck, but I wouldn't personally invest deeply in foils until I see a trend that says otherwise.
Overall, for the price Legion Lieutenant is a great value at about $1. Vampires are always popular trade binder fodder, at the very least. This is just a solid investment for any Magic player who likes to collect tribal staples or just popular Tribes in general, but it's also a great $1 card for evening out trades or swapping pieces for spare parts needed for decks.