That's the thing: it doesn't have comparable front armour to the super heavy tanks. Its front armour is barely better than an OKW Panzer IV, which has 234.
All the Churchill's abilities are geared towards close combat: short range grenades, SMGs on the side, smoke emitters originally designed to make a pathway for infantry. Therefore it sacrifices high frontal armour in favour of high rear armour.
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What makes it so tough is the metric shit-ton of hit points it has.
240 armor is high a Stug which is a dedicated AT units has around 71% to penetrate it at max range while a PzIV 46%.
Grenades are sort range but they are useful vs soft target and Churhcill has enough HP to rest snares. This is only ability geared for CQC but only vs soft targets.
Side Lmg (noy smg) have the stanard 35 range most tank Lmg have, the ability is not geared towards close combat.
Original design of smoke is quite irrelevant, currently it is a stock "get out of jail free card" as some people like to call them, the ability is not geared towards close combat.
In addition Churchill has very high rotation and acceleration and can turn and face enemy units.
The unit can fight at close but can also fight at long range.
So no it does not sacrifices frontal armor, it simply has the highest rear armor and one of the highest HP pools.