One of the most appealing factors in exowomb use is no longer having to go through pregnancy oneself. Why, then, would anyone have an exowomb implanted, negating that huge benefit?
Pregnancy might still be inconvenient, but will be nowhere near as much as with the natural option, and is guaranteed to be uneventful. Birth is fast and easy. An engineer's womb is capable, like most ectogenesis pods, is capable of bringing almost any animal to term. It borrows healing pod and morph growth technology to shorten gestation; most fetuses can be brought to term at a twelfth their natural rate.
The real benefit of an engineer's womb can only be realized, as its name suggests, by a genetic engineer. The womb runs a feed into your mesh inserts (or directly to your cyberbrain, if applicable) giving constant updates on current its current pregnancy. What's more, the womb is equipped with a suite of gene-hacker's tools, capable of gene-therapy and bio-modification throughout gestation. With only mental commands, an engineer can modify the fetus on the fly, with instant and constant feedback. Experienced engineers know that this constant feedback and at-hand tools is the difference between good results, and great.
An engineer's womb is cyberware [High]
An engineer's womb can also be used as a small (~limb sized) healing pod in an emergency.