Yes but it’s also a question of your game’s relevance.
Just because we can say “a crack of your game IS possible” (and it is, that is a statement of fact. As far as I’m concerned it’s a fool’s dream to believe your game to be even theoretically uncrackable) that doesn’t mean that it is necessarily easy. There are steps you can take to make it more difficult, and subsequently make it less likely that any given person will succeed.
Now, the deterrent effect isn’t much in the world of software because once SOMEONE overcomes your deterrent, all they have to do is slap it up on a site somewhere and everyone has access. But it’s also worth bearing in mind that the multi-million dollar games with “uncrackable” new anti-tamper packages being touted in all the magazines are like a dare to the cracking community. Those companies are basically begging the best and brightest to give it their best shot.
A moderate and sensible degree of anti-cheat won’t stop the powerhouses who are writing custom cheat bots for 4-figure sums to people who have a pathological need to have the best killstreak in Battlefield 4… but you also have to ask yourself whether those people will really be interested in YOUR game. My house doesn’t have the same degree of security as a bank vault but that doesn’t mean I just go leaving my front door wide open, you know. I’m sure my front door’s lock wouldn’t stop some Italian-Job-esque heist attempt but it helps deter amateur opportunists. I think taking the same approach to anti-cheat is sane and sensible; you won’t stop the select few who can crack freaking anything, but as long as those people aren’t feeling motivated to crack your game you can definitely stop the few people (from the much larger pool of amateurs) playing your game who might know a little bit and want to cheat but aren’t good enough to overcome moderately competent security measures.