Not entirely so. Via iplayer and I believe all4 you can stream live tv. Apps like TVplayer can be used to watch live tv too, but bear in mind you'll only get SD picture quality overall (iplayer is hd-ish).
There are plenty of add-on boxes out there that can be used to access the apps. -- Amazon FireTV, Roku, NowTV, etc. Freeview Play is not your friend unless you have an aerial. Depending on your location, you might get away with an indoor aerial, but you really do need an outdoor aerial to take advantage of any Freeview Play tv/pvr.
Clem