In one of the videos from Pete Clarke's From The Ground Up course, he talks about how a "secret" to being miles ahead of the population is raising merged vs range bets as opposed to the common strategy of raising polarized.

An example he talked about was BTN opens, BB defends and BTN cbets 1/3 pot with his entire range on 742r. According to him, we should be check raising hands like some 7x, A4s, 2x with good backdoors and obviously super strong stuff like sets and overpairs we didn't 3 bet pre. This is done apparently to deny equity and for thin value (or fat value when it comes to the top of our range).

My question is wouldn't this leave our calling range weak and vulnerable to aggressive barreling on turns and rivers? Can't BTN just barrel aggressively and with frequent overbets to pressure our weak range? Also say we x/r a medium strength thin value hand like the A4s mentioned in the video. Turn comes a picture card. Now what? If we bet again it becomes really thin and unclear whether it's thin value or in bluff territory. If we check we give up control of the pot and equity denial.