Derrrr!
Because aircraft like this one:
Likes to snoop on our 'stuff' and aircraft like this one:
Likes to snoop on our V Boats...
Also taking piccies of their aircraft up close enables us to see what new sensors are fitted and what they may be able to detect. There are many variants of the TU95/TU142 and each has a specialised role - check out your search engine to learn more.
Also, the BEARs, BLACKJACKs and BACKFIREs don't have western transponders and so might bump into a civvy airliner as they don't trigger TCAS and their altimetry is in 'metres' rather than feet. So escorting them around in formation in our FIR is important as our transponders are visible. I think there was a serious AIRPROX in the Baltic very recently due to this very fact - don't forget that civvy ATC RADARs mostly rely on transponders and not primary RADAR returns.
Finally, some of the afore mentioned types can carry air to surface missiles (ASMs), nuke tipped, that could be used as a 'first strike' weapon without the type of warning you get from BMEWS at Fylingdales. Wouldn't you want "eyes on" if an adversary was flying in your FIR and within striking distance of your key assets?
Strategy lesson over...
LJ
PS. It's certainly not 'playing' and QRA is a deadly serious event for all concerned at the sharp end!