Last year we had first frost in Chicago Sept 12. Did not kill tomatoes but did in all flowers on cukes. What I get in Sept from tomatoes is a bonus. The reason why I start early so I too can have 6 weeks of the season instead of 2 weeks in August.

Early ones also continue fruiting till the end of season, UNLESS it is some kind of ONE SHOT determinant. Even some dets fruit continuously, like SiletZ, Legend and many more.
Staggering make sense (to me ) where you have a very long harvest season and some plants get old and tired. I don't think it is the case in zone 6 in NJ.
OTOH, some early varieties are about 2 - 3 weeks earlier than the mid season. Plus most of them have small tomatoes, slightly bigger than cherry, such as Matina, Bloody Butcher and Stupice that I grew last year.

Sey

Last year I did both indeterminates and two determinates (Marglobe) and got both a flush of wonderful early tomatoes and more than I could eat throughout the season from the rest of the maincrop plants. The Marglobes completely fizzled out after the flush of ripe fruit, but they were small and worth the space.

It depends on the varieties you grow. And early is not good for everything.

Some of them, like cherry tomato, can grow to very tall. In the fall, the plants are too tall and the fruits are very small. The plants are not manageable and you'll have to prune the bush.

When the plants grow so early, the lower leaves would fall. After the hot summer, the plants do not have so much energy to produce good quality fruits.

This is why in very hot region, like in Texas, you grow tomato either early or late. And the plants do not do well in the hot sun.

I got tons of fruits from my cherries into October last year. The plants had EB and Septoria too