Is he calling a check/raise on a Kxx flop with JJ or QQ? What about a Axx flop? If he has a mid pair he has a tough decision if the flop contains an overcard
He's going to check behind second pairs 80% of the time or flat call with everything he want to continue, if we lead strong at him.

plus his range is way wider
you can't say JJ+ when he min 3b you
it's more like 99+, ATs+, AJo+, T9s+, KJs+, KQo
That's why, either fold or 4bet him. He'll 5-bet shove top range (super easy fold to us) and call with his ass-end of range, which will allow us to actually have some +EV, when we flop a hand and decide to play for stacks.

without a read on the guy do we really want to invest a bet preflop when we can see a flop getting 3-to-1?
If that bet will narrow villain's postflop range to something like AT-AQ, KJ+, T9+, 88-TT and get him to fold most of this postflop, then yes, we do want to invest a bet because it's good investment.

Sometimes we'll take it away post-flop if we see that his line is weak
It's much tougher pull fancy float vs unknown. When we don't want to give up yet, then (in that specific spot) 4bet-bet will take it away way more often, because it looks more straightforward.

not enough to 4b unless we're doing it as a bluff
If it's small 4bet, then it's not a total bluff, maybe slight overrepresentation of a hand. Villain already demonstrated, how he sucks at sizing the bets and probably hates folding pf, so it's more value play, than a bluff play.