Ok, but let’s look at a country like Finland.
They live next to an enormous, aggressive neighbour. Should Russia decide to go Ukraine on them (is that likely? It’s besides the point for the discussion on conscription) they need hundreds of thousand of soldiers to enable a credible defence. If they have that as a standing, professional army, society is wasting huge resources keeping people in uniform that could be out and be productive members of civil society.
And should they wait until things looks threatening they don’t have the time to train this army, nor the time to integrate a sudden, enormous new component in a the standing army that’s used to working only with itself.
Instead they choose a system of conscription. Soldiers are trained, then sent home to be productive. Occasionally they’re recalled for supplementary or refresher training, when equipment or doctrine changes. Invariably, they get older, eventually too old, so while they may remain part of the reserve, they’re recalled less in favour of their younger colleagues.
Undoubtedly they won’t be as effective as a standing army if recalled in war-time. So they’re lead by professional officers, keeping only the squad leaders and platoon leaders in the reserves while anyone of another function are in the standing army. The sergeant’s and lieutenants in the reserve are recalled more often, many having some contract that requires many weeks of service every year.
This makes it possible for Finland to maintain a credible defensive posture without keeping half a million soldiers in their standing army, doing nothing productive for society and costing a fortune.
Conscription has a place when the country is small, the threat nearby and unpredictable.
I can’t help but wonder if your opinion is enabled by the advantaged position of having an ocean between the society you live in and its potential aggressor. Most European states with a front towards Russia has found conscription the best compromises between the vast cost of maintaining a professional army large enough and keeping their societies productive in peace time.
I would agree, but the way, that being trained to be a soldier in a conscripted defence isn’t that particularly useful to the individual receiving the training (other than a change in attitude towards accepting challenges, which many employers later appreciate). It can feel like a waste of YOUR time. In this case, however, the usefulness is for society at large, something I know has been going out of fashion in this day and age.