I have used a simple method for seed starting in the past where I planted seed in trays and kept them indoors until they germinated, then set them on the light stand. I also set trays on top of the shop lights where the ballast heat would keep the trays warm. This was not getting the job done with my light stand in the basement where 60 degrees is the average temperature. I also wanted heat mats that were specifically 2 feet wide by 4 feet long so that they will fit on my light stand shelves. I purchased 2 https://www.amazon.com/dp/B087M7138K and received them the end of January. They have been more than worth it! Seed germinated in record time. The heat mats use temperature probe thermostats to regulate heating. I set them to 85 degrees which they held between 81 and 85 degrees.
Pro-tip, if you are watering seedlings, try using warm water at about 100 degrees. Putting cold water into a seed tray just slows things down. Warm water speeds up germination.
I bought the same mat as well. I am not only using it for germination. My grow room has 61F-70F and this seems not enough for peppers. I am going to keep them on the mat that is set for 68F. This way at night they will be between 65 and 68(hoping for 68) and during the day sun and lights will increase temperature to 75.
I use heating mat to germinate indoor seeds too. It can really speed up the germination. I have tomato seedings grow above the soil level in 5 days. I noticed the germination rate is higher than those without the mat. Besides germinating seeds, I also use it for root cuttings.
The soil dries faster with heating mat though. Few years ago, I was trying to root hardy kiwi scions , but I failed. The main reason was that I failed to watching the soilless seeding mix. The mix got too dry and the scions were all dehydrated.