Opposite a lot of nondescript hands where partner will pass if you do, you do want to defend doubled. You really expect partner to bid or double on xx, Axxxx, Jxx, Jxx for example or xx, Axxxx, Kx, xxxx. If you think partner doesn't bid 4H on this, there are plenty of other possibilities. And opposite a lot of nondescript hands where partner will pass if you do, you do want to defend undoubled. By not forcing opener to bid anything but pass, on hands where he wants to defend, you can eat your cake, and have a part of it. On many of those hands where you could succesfully double, your wide-ranging 4♥ have already given you a plus-score, on a hand where you would normally go minus. Of course nothing is bulletproof, but a "penalty-like" double seems to take care of the least amount of problems.