Why choose monitor instead of towers and more questions

Hi all,
I just started to dive into the hifi world. In my youth i was an avid Technics lover (didnt know antything outside of Sony/Philips/Pioneer/Onkyo).

Now the world is thanks to the internet an onbrlievable source of information.

Just a few noob questions.
I see monitor/bookshelf speakers (often on a stand), and full size towers. No advantage for the monitors regarding the space you need for them as they are 1 mtr high with stand. So why still choose them?

Thinking about a 5.000-6.000 euros budget, and spending it like:
Lyngdorf tdai1120
Lyngdorf fr1 or Sonus Faber Sonetto on wall or Dynaudio Rubikore on wall
Technics SL1200 turntable
Any cd player

Or going the Cambridge Audio Evo 150 plus Evo CD way…

Or thinking a bit about the Advance Paris 150 connect amp(with built in cd player)

Too much possibilies..
Anyone better ideas?