Do we even use purple omens/ omens of light?

They're used for crafting. Some people craft lightly with what they've picked up like you do, others buy all their omens and mass craft to sell. Anything you sell on the exchange you are selling at market rate to people who value it at that amount.

So yes people use them and their price at the market is a direct correlation to how often they are used and their drop rarity.

They get used in high end crafting. If you’re not crafting seriously juiced up items, it’s generally more profitable to sell them to those who are.

That said, you do you.

At the end of the day its just pixels. If you have the time to earn it back, why not experiment a bit.

Yeah people use them but the item usually is of higher value than the omen itself lol

I've only used them when the item is so close to either what I want or if I think I can profit after accounting for the value of the Omens.

Then, if I don't get the desired result from the first use, I have a couple of times used them out of spite and stubbornness..... It has never worked out well, shouldn't have done it.

I make my money by selling citadel fragments, blink spirit gems and breach splinters. In exchange I use the divines to buy all kinds of purple omens/jawbones for crafting. I’ve made 3 crossbows that made me profit and a bunch of failed fractures in the process. One made me 5800d and another 4500d. It’s a stressful part of the game but when it hits it’s a very rewarding feeling.

Generally people look up the total value of the end result of the item they’re trying to make, and determine which crafting method to use based off that. If the cost of a light is more expensive than what you’ll sell the end item for it’s not worth using one, unless you’re SSF.

Omens are used in mid to high end level crafting.

For example you have an item with 1 or 2 dead mods, but the rest are perfect. It might be a good idea to whittle couple of bad mods with perfect chaos orbs. Advice here is to look up your chances at improving your craft at poe2db and craft of exile. It also might be the case that on average you are better off by selling the item and omens and buying improvements from the market. This is not available on ssf though.

High end crafting is all about planning and calculating. Before going into high level craft you must have all the crafting materials available to you and the plan of how you want to achieve the end craft before you start. This usually requires large quantities of omens.

I like Belton for explaining this stuff, he goes into a lot of detail. Ghazzy is good as well, he does less detail, a bit more beginner friendly stuff. There are several others, you can find them on youtube.

You either dont use them at all or use them a lot to beat random and obtain target T1 mod on a mirror tier item.