If your overall medical status is such that you are not a safe and appropriate candidate for outpatient tummy tuck surgery, then by all means, hospital care is reasonable. That being said, I operate in my own fully-accredited in-office surgical facility (and have done so for 24 years), and do dozens of outpatient tummy tucks each and every year. Safely, and comfortably for the patient, as well as less expensive for better care.
How can my office surgical facility be better than the hospital? Well, first of all, my office does not expose you to sick patients or nasty bacteria--only healthy, elective surgery patients in my operating rooms! Second, our anesthesia is better than the (safe, routine, cheap) inhalation anesthetic you receive at the hospital. For more information on this, read my article (click the About tab on my profile page) on this site titled: "Is TIVA (Total IV Anesthesia) or General Anesthesia Safer?"
Assuming the plastic surgeon you choose to perform your surgery operates at an accredited surgical facility (either his or her own, a stand-alone outpatient facility, or a hospital-affiliated surgicenter), you will get identical monitoring as you would at a hospital, including availability of "crash cart" medications, defibrillator, malignant hyperthermia medications, etc. What you won't have is the higher cost, increased overhead (to pay for all the patients who receive hospital or ER care without having insurance), and things you don't need like MRI and CT scanners, angiography suites, and lots of doctors of specialties not involved in your care.
Also, any outpatient who goes home has the same prescription pain medications as the hospital, just not a nurse to inject them into your bottom! In the recovery room at an outpatient facility you will still receive the same intravenous pain medications used at the hospital, and perhaps even more thoughtful ways your surgeon has learned to control incisional pain, muscle spasm, nausea, and swelling/inflammation.
So if you are the typical young, healthy patient that usually asks for tummy tuck surgery, you have no reason to go to a hospital (unless that is the only place your surgeon operates, or if the anesthesia practices have such a high PONV--post-operative nausea and vomiting--rate that patients that could have gone home with better anesthesia are "green and barfing" and must stay to get that under control!)
See several ABPS-certified plastic surgeons who have busy enough practices that they operate their own AAAASF-accredited surgical facility; you will get not only safe and better anesthesia, but likely a more experienced surgeon and superior cosmetic result. Best wishes!