The biggest difference between the Nintendo Switch and the Nintendo Switch Light is that you can’t connect the Switch Light to a TV. There’s no dock or port designed for TV connection.
That’s not the only compromise you’ll have to make as the Joy-Con controllers aren’t detachable. You can’t put your Switch on a table and keep the controllers in your hands for instance.
Of course, you can buy Joy-Con controllers or the more traditional Nintendo Switch Pro controller separately. You’ll have to find a way to charge your Joy-Con controllers