They don't stop hypo's and high's but go a long way to keeping these to a minimal, Pumps aren't magic wands that plug and go, the getting up and running it a steep learning curve and hard work, but saying that the benefit the give is second to none once you are up and runing...
You can use them in a proactive manner..
Stablizing out the basal (background level's) also you can build between 4 or 5 (dependant on pump) different basal profiles, so one for school day, one for home days, anothers that cover different regular activities they might do...
The 3 bolus's help to better match food adsortpion to give stablier control..And it's a press of several buttons to key in the dose, rather than having to inject with an insulin pend
Infusion sets only need to be change every 2-3 days depending whether you chose the metal or teflon infusion set, there may be times a problem arises and infusion set needs changing earlier, but less stress involved than injecting several time a day...
You can set a TBR (temp basal rate) up or down, if you change plans and activity is more or less than planned.. You can also use this to tackle the extra insulin needds when they come down with the lerggies a lot easier and quicker than injecting, and of course if you have to correct an high BG then it's a case of pressing a couple of buttons to get the dose required..
It makes keeping up with there ever changing insulin needs due to growing spourts etc..
Down sides in the main is that if for any reason the supply of insulin is stopped, such as air bubble in the tubing or blockage BG can climb quickly, as there is only 2 hours supply of insulin in the body at any one time, so it does higher the risk of DKA... But regular checks of tubing for any air bubbles, and BG's all go towards helping to pick any pending problem..
Oh there is a facility to lock the pump buttons so little fingers don't give themselves an extra dose of insulin or two..