You need to know just how dirty the process media gets. Y-Strainer screens are smaller in dirt holding capacity than the strainer baskets used in basket strainers. So, in a given application, a basket strainer will go longer between cleanings than a Y-Strainer will.
So, if the application requires infrequent cleaning and the process media is environmentally safe, a Y-Strainer should work. If the opposite is true and the strainer will be cleaned often and the fluid is less than friendly, a basket strainer is the answer. If in doubt, select the basket strainer every time. It may cost a bit more but will stay in service longer between cleanouts, and it will be easier to clean.
And remember, nothing is quite as useless as a strainer without a basket or screen. If the basket breaks or gets lost or damaged, the line is out of service until a new one is located, purchased and installed. Having a spare on hand avoids this downtime problem.