Reliable penetration helps against volks blobs... How?
The penetration on the comet may not match the panther but it's still world's above any other allied medium and better then many tank destroyers.
And yeah it's true the comet doesn't have a pintle mg but the white phosphorous shells and commander upgrade are easily worth more. Also non vet free blitz.
I am not saying the comet is overpowered or the panther is underpowered but don't sell the comet short.
It's about task distribution. I'd rather have 1 strong AI unit + 1 strong AT unit than 2 units who perform mediocore in both ways (allies have plenty of those units). The Comet relies entirely on it's main gun to hit the infantry which makes it extremely RNG based.
The penetration is not better than many tank destroyer. The only tank destroyer with worse penetration is the M10. All other allied mediums (TD excluded) have a worse penetration but also don't suffer from horrendous tech costs and they cost 140 fuel or less. The Comet requires 225 (bolster and weapon upgrades included) fuel to tech. Even Ostheer has it cheaper.
The phosphorous shells are powerful, if they'd actually work and not fail every 2nd time. The Vet bonuses are pretty meh and don't buff the Comet's raw firepower or durability, such as reload time and health (unlike the Panther).