Their ID systems were more or less identical to those in other games.
Angband's system is ridiculously pointless. You have unlimited time and an unlimited potential ID scrolls. You can't compare something like that to games like Brogue where you need to squeeze every last ounce of utility from your limited supplies.
Crawl's system is mostly pointless too. Remove curse and identify scrolls are plentiful so most of the time you're just doing busywork with no real consequence. It isn't a complete waste like Angband, though. Sometimes cool things happen. Like if you wield-ID a weapon and it turns out to be distortion, that's going to have an effect on your playthrough. If you wanna switch you have to consider the risk of lethal damage or going to the abyss. Maybe you'll live with it until you can survive the worst it can do, or maybe you'll take a risk to get rid of it right away. Either way it's a real problem and the way you choose to deal with it has meaningful consequences.
Brogue is a nice counterexample to Angband and Crawl's systems. In Brogue if you desperately need a specific effect from a potion or scroll, you can probably find it by burning through all of your items, but that will potentially involve a lot of waste. Or maybe you'll get lucky. If you wait until you find a detect magic potion, you can make much more informed decisions. The detect magic effect creates a lot of situations where you can try for a chance at an immediate benefit or hold off until later to get better odds.
Use-IDing scrolls might cost you a scroll of enchantment when you don't have anything good to enchant, and that will weaken your character for the rest of the playthrough, but the longer you go without testing scrolls the longer you'll have to survive without their advantages.
If you take an unknown item from a treasure room and it turns out to be bad, you have to weigh the hunger cost of swapping for a different item. If you had used an ID scroll or a detect magic potion you might not have had that problem.
Brogue also keeps track of which items you've IDed and tells you how common each item type is, so even when you're using unidentified items you can make educated decisions. If you already know all of the important positive potions you can feel free to throw your unknown ones at enemies.
There are a lot of cool things that can come from roguelike ID systems. Don't judge all roguelikes based on Angband, it's a terrible game with almost no redeeming traits.