Cheaper to use a drone for spotting instead of a FIST unit. That's what's working for the UA.
Kamikaze drones have a role for the smaller units, but at the battalion level, it's better to use a surveillance drone to coordinate fires from mortars, MLRS and artillery. The rounds fired from these systems typically have longer range than a drone, a higher rate of fire, and larger warheads.
I think these are pretty complementary. Switchblade 300 is a 10km range Javelin (same warhead in fact) with integrated surveillance capability that can go beyond range of sight. It is not there to replace mortars, artillery and MRLS, which are area weapons.
Artillery has been used by Ukraine, and by a lesser extent by Russia, extremely effectively as a precision weapon against all kind of targets, including MBTs.
Kamikaze drones have a role for the smaller units, but at the battalion level, it's better to use a surveillance drone to coordinate fires from mortars, MLRS and artillery. The rounds fired from these systems typically have longer range than a drone, a higher rate of fire, and larger warheads.