LinkedIn works wonderfully well if done right creating the right audience for your product ( almost for free ! ) . All your points are true but which social media doesn't have flaws.

Name me one good platform for b2b business networking ?

If you ask me what are Facebook & Instagram , I won't be able to give you a straight answer ... They are everywhere. Its sometimes scary to open their app & lost there for hours.

LinkedIn gives you precision b2b networking !