During the change I refered to the OSM wiki:
https://wiki.openstreetmap.org/wiki/Tag:amenity%3Dbus_station

https://wiki.openstreetmap.org/wiki/Tag:public_transport%3Dstation

Since here can enter only PEÜTK (Põhja-Eesti Ühistranspordi keskus) allowed transport, it is not allowed for usual traffic. Here only buses stop, the regional buses. Couple of local TLT buses but others are regional buses. No long distance buses in the classical meaning altho buses here do connect cities that could be under special occasions still be considered long distance buses. But according to OSM wiki, there is no such distinction between long distance buses and other bus route types. The requirement is public transport which buses here that stop definitely are, besides other requirements that 
Balti jaam has two public transports - train and buses. If bus station is wrong, then railway station should be expanded to accomodate both of these terminals.
This is not a bus depot too where buses stay overnight or get serviced like TLT has at Kadaka tee.
The other way here would be this but it doesn't exactly suite well also:
https://wiki.openstreetmap.org/wiki/Tag:public_transport%3Dplatform

Either way, it is not a parking lot there, its a place where numerous bus routes start and end along with possible route change between other public transportation methods namely train, railway and local TLT buses.
Buses may park there overnight but its only for PEÜTK allowed buses.

Unless there is something more definitive or better to use instead of amenity=bus_station or public_transport=station for which I am open to use here instead, instead of just deleting the parking lot.