The topic's all about taking the spyglass, don't think you can get away with a simple "it works for me", you gotta be more specific to convince anyone. Even brand new crew can spot enemies, sometimes without you even telling them. You're sacrificing a huge portion of your mobility to do someone else's job, a job that isn't so necessary (if YOU can spot the ship, you already see it, from then on it's just a matter of keeping your wits about you). Spotting is certainly very helpful and crewmembers that spot for you will win matches as that reduces the ship's reaction time considerably, but your reliance on that marker can be considerably reduced with practice in exchange for a significant mechanical bonus, you're getting more DPS and less damage just by keeping your guns in arc and range and fleeing in a direction you won't be followed.
I can see the spyglass being useful for newer captains that can't quite communicate with their crew yet or maybe on ships where you know your crew doesn't speak English and won't spot or POSSIBLY on a sniping ship where there's a chance you're the only one that can see a ship that needs shot at, but for anyone capable of getting those tricky spots in the first place you personally are not going to benefit that much from the marker anyways. Microphone or text instructions are often faster than the three or four seconds of mad left-clicking it sometimes takes to spot something with a spyglass.