I suppose they might be useful if they help people see that a 10.5kW electric shower uses as much electricity in ten minutes, as a modern LED lightbulb uses in 175 hours. Or as a microwave on standby uses in 24 days. And pay attention to the power-hungry appliances, not the trivial ones.
A smart meter is actually not very good for measuring particular appliances. You can get a plug-through watt-hour device for about a tenner that will measure usage of the appliance plugged into it. Or you can get electricity monitors that were briefly popular before the government decided to make us all pay for smart meters. Many monitors were put away into cupboards and surface on ebay for a few pounds.
But I can tell you what it will say.
Modern energy-saving or LED lightbulbs use so little electricity that you may as well forget about them. So does a modern extractor fan. Devices on standby use so little that you will not be able to accurately measure it. So do phone chargers and the like.
A tumble drier uses a lot. A fan heater uses a lot. Any electric heater uses a lot, and all of these are liable to be used for long periods on many days of the year.
A washing machine might use about 3kW, but only for about 10 minutes for each 60 degree load. A kettle or toaster the same, but only for about three minutes. For a single mug of tea or coffee, you can heat a glass jug containing the correct amount in a microwave more cheaply.