It's just a setting. Sure, you have more time to gain skills and accomplish things, but it's up to the player what they choose to do with that time. Most people I've seen playing on long life span (or even aging turned off) don't even do it because they want to sit there grinding through skills, careers and aspirations, they do it to have time for both normal, realistic achieving as well as storytelling. If anything, people who specifically want to accomplish an unrealistic amount of stuff tend to be the ones doing super sim challenges and have life spans set to short just to challenge themselves. Or they're players who just aren't fans of generational play and want to experience everything the game has to offer with the same sim(s). Even for the latter I don't consider the setting cheating. It becomes cheating if they use cheats to achieve everything and maintain needs and relationships while doing so.
I have aging turned off entirely and it's my primary mode of operating unless I'm adhering to strict rules for specific challenges. Besides the normal grind I have plot points to get through and as a rotational player I wouldn't be able to do that if sims were aging up too quickly. If I chose to use all that free time to just grind aspirations, skills and money to infinity then that's on me, a player choice, but it's not inherently tied to just the setting. Even though my aging is turned off I still keep things realistic. Sims achieve only one primary aspiration in adulthood, max a realistic amount of skills, make the amount of money that fits their career, and die off when I deem their life to be over, be it of old age or player decided deaths for plot. I just don't want to stress over having only x amount of time to get through storylines and also do the necessary things of raising children, career advancements, skill gains etc. My generations of sims would feel boring to me if I didn't have sufficient time to flesh them out.