This makes engagement with cannons or infrared homing missiles easier because of the minimal lateral target movement relative to the attacker and the fact that the hot engine exhaust nozzle(s) are pointing directly at the attacker, making the infra-red seeker's task of tracking the target much easier.
[1] Missiles typically have a very high chance of hitting a target in a tail-chase engagement because of the much reduced closure rate.
Its only real hope is to fly away from the missile fast enough that the overtake rate is reduced to virtually nil, and then force the missile to follow it through several turns, bleeding off its residual energy and causing it to fall away.
This greatly reduces the effective range at which these munitions can be used.
In addition, in the case of an engagement between two aircraft, the attacking aircraft will probably have to engage afterburner and chase the target down, using up a lot of fuel in the process.