Millibars are the familiar unit for people in weather forecasting. Weather maps have been issued in 4 or 5 mb contours for at least half a century and probably longer. People in the weather business talk to each other in millibars and not inches or mm of mercury. If you were in any given weather office, private or government, you would hear people talking about for example a 965 low meaning it had a central pressure of 965 millibars.
All you really need to know about millibars is that 1013 is the global average and anything over 1040 is quite high, anything under 960 is quite low. I do have a home barometer that measures in inches so I’m used to making conversions in my head. This has probably been stated earlier in this thread, but 1000 millibars equals 29.53 inches and so 1050 millibars, about the highest pressure most people see in an average winter, would be 5% higher. That would add 5 x .295 inches or 1.48 inches rounded off, so in other words 31.01 inches and I think you’ll find that your home barometer shows this as being fairly high. A very deep low at 950 mbs would then be an equal amount lower, or 28.05 inches.
Sometimes in metric countries you will hear pressure given as kilopascals, these are scaled like millibars but ten times smaller so that 1000 millibars would be 100 kilopascals. So if you ever hear that type of pressure reading just multiply it by 10 to convert to millibars.
That typhoon last November in the Phillipines reached a minimum pressure of about 890 millibars. You can see why weather people prefer it, the relativity aspect is very obvious since the mean is more or less 1000 millibars.
I should add that in weather forecasting, all pressures are converted to sea level. If you live some significant elevation above sea level, your actual pressure will be a lot lower than the sea level pressure on the weather map, and your home barometer may or may not be showing that. The best way to check is to wait for a time of slack high pressure when your local TV station pressure (whether given in inches or millibars) will be the same as yours even if you’re some distance away. The same “sea level” pressure, that is. To give some idea, the upper air reports given from radiosonde balloons are given not at standard heights but when the balloon gets to standard pressures of 850, 700, 500, 300 and 250 mbs. The 850 mb maps that are then derived from those observations average about 1,500 metres above sea level which is about 5,000 feet give or take. The 500 mb maps are at an average height of 5,500 metres which is close to 18k feet. So if you live in the plains states you might be at some elevation almost up to 850 mb, which means your actual outside air pressure is really 900 mb when the sea level reading is 1000 mb. If you live in the Great Basin you could be up around 750-800 mb. At the top of the highest peaks in the Rockies you are close to 600 mb and when you’re at cruising altitude in a jet plane the outside pressure is about 200 mb. No wonder they have to pressurize jet aircraft.