I would say all BF Games are for or about the MP. Sure Hardline (along with BF3, BF4) have a Single Player Campaign but they for the most part are a one time play-through. I would not pick up BF Hardline for the SP. I played the
Beta for a while and it is on the fun side but it also does lack in a lot of what BF is in BF4 or even BF3.
There is of course and exception to BF being mostly MP Games or exclusively played for the MP. BF Bad Company had an excellent SP and some of the best Characters. Hardline will be forgotten in it's SP and even MP by next year. Get it if you want but I would
say at least wait until it is dirt cheap at about $9 (US).
I bought this game and have regretted it ever since. The single-player, while good, lagged something fierce (and that was single-player!). The multiplayer is nearly impossible to play due to constantly bad spawns - you can barely take a few steps before
getting killed (I can't even tell you how many times I've actually spawned directly in front of at least 6 enemies, all looking at me - it's a veritable firing squad). IMO, a game that doesn't let you play it isn't a game worth owning at all. Skip this one
unless you're a die-hard BF fan.