Strap locks are generally designed for electric guitars, because electrics are more often heavy, and it's heavy instruments that tend to shake their straps loose.
Hence, locking buttons are usually attached with a long wood screw, buried into the solid wood.
Acoustics tend not to have those deep solid wooden areas. If you like to have your strap attached at the heel, there may be enough wood there. At the tail it's unusual to have much depth of wood.
So, you would need an alternative way of attaching it -- perhaps a nut and bolt rather than a wood screw. The advice you've been given is probably sound -- a luthier could advise.
I personally would not attach a locking strap to an acoustic -- for me, the strap never falls off. The old trick of using the rubber ring from a Grolsch bottle is sufficient.
Fender and others sell similar rubber rings. There are also plastic devices that fit over an existing button and twist to lock.