It gets a little muddled as traditional toners (usually heavy alcohol laden ones) were there to clean up after a crappy cleanser. They're useless, if that's what you're using them for as you just need a better cleanser.
The acid toners are chemical exfoliators and are beneficial to many (though irritating to some) and preferred over physical exfoliators (scrubs) as they're less aggressive to the skin (microtears) and help with cell turnover and cleaning out pores. The only thing they have in common with old fashioned toners is the stage at which they're used and that they're liquid, naming them toners is a bit unfortunate and confusing imo.
The pH re-adjusting toners have their place as pH in skincare does matter, however if you're using badly formulated products that require a pH readjustment add-on product, it's pretty much like the cleanser, you need to just get products that don't need an additional product to make up for its shortcomings. Though I should point out that some pH dependant products require wait times and a pH re-balancing toner would eliminate that wait time but again, a well formulated product even with very specific pH shouldn't require a wait time. There are cases where the water from your tap is a very undesirable pH, raising the pH on your cleanser undesirably and if you can't do anything about the water affecting it this way, then a pH readjusting toner actually makes sense.