I feel like the people who say "why do you need that" or " you don't need that" are the same people that say pellet smokers are cheating and should be driving their paychecks to the bank to deposit them manually.
You don't "need" a lot of things but if they make things easier, better, faster etc. why would you not want them? I mean, you can cut your grass with scissors but, the invention of the lawnmower was pretty handy.
I personally can drink a pot of coffee and go straight to sleep so I like the kick that comes with a pre-workout. Especially when everything in my being is telling me to slap the snooze at 4 am. It's been my experience that a good nitric oxide greatly improves your strength and stamina, helping you achieve whatever fitness goal you may have, along with lowering BP and increasing blood flow. That's good for even the ones who don't have any particular goals.
Amino acids are proven to help muscle recuperation. While you CAN get this from food as the naysayers have brought to light in this thread. It's a supplement, its meant to supplement... if you're on a calorie deficit program and don't want to take in the calories that come with a full meal, or if its just convenient to take a supplement vs preparing a meal, then they certainly have their place.
To further that point, GNC Wheybolic protein, particularly the cafe latte flavor is the best tasting, no sugar protein mix out there IMO. Low cal (not a meal replacement) and low carb. It's perfect for those strength training and looking to trim the fat. I've been on this long game approach of keeping body fat low while gaining muscle and strength and it's helped out tremendously.