There are two types of radiant that use electricity, direct cable and electrically heated water. WHEN TO USE ELECTRICAL MATS.
Although I do recommend using electric boilers for large new construction because of the ability to change fuel later if electrical rates increase.
There are times that electric mat systems do make sense and are feasible. Electric water heaters simply do not have enough Btu output for space heating.
If you have a small area that you need radiant.
I do recommend the electrical mats for small areas such as kitchens and bathrooms especially if you want to remove hydronic baseboards or radiators.
Remember when you take a shower you are using stored hot water not the water that it is being heated.