If you send the digital back to the factory every year to be tested for accuracy so be it but my main tool for gas pressure testing only is dial or water filled manometer. The water one is always true. Years ago I had a mercury one which was given to me by a local natural gas company BUT it has been disposed of since mercury and the enviroment (breakage) can always be a problem now days. Years ago if you broke one outside the mercury disappeared into the ground. Now you have to call a hazard waste disposal unit and pay 3000.00 for the clean up and disposal cost. LOL
I do have a digital available (many still in the box) since all my guages are supplyed to me for free as test/training demos. Some are very good BUT keeping them accurate can be a problem. I will have to admit those digital guages sure can make a lasting impression especially to the uninformed like customers.