I rarely use the dealer because he costs T-cash and I don't make the best use of him because I forget that I have him. But twice now, I have gotten a 60% off deal (10 days for 36 t-cash) and jumped at it. How could I not?
I rarely use him for products, but I buy jewelry and ore from him since I never have enough of either, especially copper ore.
The trick I discovered is that when I buy something from him, I set a timer on my Echo Dot for one hour, when he will be available again. I also set timers for anything I want to be sure to follow up on, such as flipping boats for a boat task or refilling the zoo stores when the hot items are high point values. Yes, when the timer goes off, I have to rememberr WHICH item I wanted to deal with as soon as possible, but that usually only involves checking two or three stores/factories. If I really think I'll forget, I set a reminder rather than a timer, which lets me have Alexa tell me "zoo" BUT doesn't keep going off until I say "Alexa, stop" like the timer does.
Of course I could use a regular timer and accomplish the same thing. But I didn't. Finding it and then remembering to drag it around from room to room so I could hear it when it went off was too much of a nuisance, not to mention I often have two or three timers running at once for different tasks. I find Alexa much easier to use. YMMV.