These days, I simply buy the cheapest generic sandwich bags and snip a tiny hole in the corner for piping, writing or flooding unless I'm using a decorative tip (such as a star or leaf tip for specific design shapes.) But I don't see why you couldn't use a Wilton or other piping bag without a tip if you have a bunch of them. Without using tips, you can get a tinier hole that gives the ability to make the smallest strings and dots.
I think that as long as you get your icing consistency right, you don't need to use tips for piping, writing and flooding.
i should say I haven't bought or used the tipless bags you are talking about...but they appear to be a lighter weight plastic than the Wilton type. So, they might be easier to squeeze.