I find the limit to be useful. It prevents random relationship drama and filler.
But I think both film and television series work great for different stories. Having television without a definitive end makes stories weirdly convoluted and meaningless as they try to change another season, just the same as the empty film sequel.
I have a 2 year old so what I find time to see is quite limited. Perhaps my opinion is a result of watching TV-shows adapted from books (Slow Horses), reality (Clarkson's Farm) and crime/thrillers with a "monster of the week" structure, but with a slight narrative over a season (criminal minds)
I think I like it because it's a classic spy thriller with comedy. Some interesting characters portrayed by stellar performers. Jackson Lamb (Gary Oldman) and Diana Taverner (Kirsten Scott Thomas) are so good.
And season four has a beautiful piece of slapstick where the self important River Cartwright (Jack Lowden) falla flat on his face in a moment of triumph