How is attacking hospitals in the Middle East an effective war tactic?

Two more deliberate attacks on hospitals in the Middle East - one a government airstrike on a Doctors Without Borders hospital in rebel-held Millis in northern Syria, which killed 13 (including 4 staff and 5 children); the other a Taliban suicide attack on a hospital in Quetta in southwestern Pakistan, where lawyers and journalists had gathered to mourn the shooting death of a prominent lawyer earlier in the day, which killed at least 70 people and wounded at least 100 more - has me scratching my head at why hospitals are considered legitimate, or even useful, targets in the various wars that plague the region.

Despite being explicitly banned by the Geneva Convention, and therefore constituting a war crime, attacks on hospitals seem to be an increasingly common occurrence, particularly in the "dirty war" in Syria, but also in Yemen, Afghanistan, Iraq and South Sudan. The NGO Physicians for Human Rights claims to have documented 224 attacks on 175 health facilities since the start of Syrian conflict, with 599 medical personnel killed in the attacks, and that was in February last year, before the recent rash of attacks. Another report by the World Health Organization details 594 attacks on hospitals and clinics in the Middle East, Africa and elsewhere in 2014 and 2015 (also, therefore, before the more recent enormities), with a total of 959 medics, support staff, patients and visitors killed.

Most of these attacks involve airstrikes, which necessarily means that the perpetrators are states (rebel groups typically do not have the resources for such attacks), foremost among them being Bashar al-Assad's Syrian regime and its Russian supporters. Both Syria and Russia claim that they are not deliberately targeting hospitals, but Doctors Without Borders (who, along with the Red Cross, operate and fund many of the hospitals in rebel areas) beg to differ. One senior MSF staffer has singled out the permanent members of the UN Security Council, four of whom - Russia, France, UK and USA - he maintains are actively involved in conflicts where medics are targeted, by funding the offending groups even if not by actively engaging in bombings (as in the case of Russia). Amnesty International have also come out and unambiguously stated that "Russian and Syrian government forces appear to have deliberately and systematically targeted hospitals and other medical facilities".

What I don't understand is, setting aside the fact that the targeting of medical facilities is clearly violating the "laws of war", why would any combatant see it as a useful tactic in their struggle anyway? What do they gain from such acts, other than a whole load of bad publicity, and a potential future trial in the International Court of Justice? Even maternity and pediatric hospitals have been targeted. My question is: why?I have yet to read a convincing explanation of the phenomenon.