ERJ-145 Captain reported Baggage Smoke EICAS warning during cruise. Flight crew executed a diversion to nearest suitable airport and completed a safe overweight landing.

Narrative

BAGG SMOKE posted while in cruise flight at FL340. [Requested priority handling] and applied QRH and diverted to nearest suitable (ZZZ) [airport] and performed emergency/overweight landing (with clearance from ATC and Dispatch also applied QRH related to overweight landing (in-flight) and emergency evacuation (after landing in ZZZ). Was unable to determine in-flight if the BAGG SMOKE was a 'legitimate' fire; or merely a faulty system indication; so assumed the worst in the interest of safety. ZZZ Approach was particularly unhelpful in this situation. They did not volunteer information (such as that XXL LOC/GS was out-of-service) that could have been helpful in the crew picking a suitable landing runway (the crew had not reviewed NOTAMs for ZZZ as it was neither our destination; nor filed alternate). Also; on final-approach; they simply stated 'Contact Tower' (without providing the frequency) thus forcing the crew to look it up on EFB and thus go 'heads-down' during a critical emergency landing; etc. A supplemental system to monitor the temperature of the Cargo Compartment (in addition to the presence of smoke) would assist the crew in determining the legitimacy of BAGG SMOKE warnings...and the subsequent need (or lack thereof) for post-landing emergency evacuation on the runway.