Our son bought us a microwave like yours when our old one died. I hadn't used any of the other facilities until fuel became so expensive. I bought an airfryer to cut down on fat consumption and use this almost every day, combined with the all-singing, all-dancing microwave, my one-pot and my slow cooker, I rarely use the oven now. It's only switched on for baking, and only then if I can totally fill it, and for a Sunday roast, when again I can use every shelf and cook sufficient quantities for spare freezer 'ready' meals.
I can't say that our power usage has declined by much, but it certainly hasn't gone up either.