Because they are the most accurate and pretty easy to tune. I have a couple of clip on and 2 stomps, a mini and a couple of HDs. It’s so dead on accurate that you have to go with the sweeten tuning because your ears are so used to not dead on perfect tuning, lol.
Check this one out. https://www.petersontuners.com/products/stroboClipHDC/
Yeah it’s actually the ease of use that makes me recommend it.
I believe you guys that those rock. You’re like 1/3 of the way to a used darkglass micro tubes/ alpha Omega/Adam at that point though. One of those things tunes and the other one makes cool distorted bass sounds and has a DI out and is a DAI and has amp sims and is a tuner. I think this is also my “just tune by ear 5head” bias coming out but I can’t wrap my brain around spending that much on a tuner.
LMAO
Yeah I’d love to be able to tune by ear as well. I’m so used to when I play Fretless especially unlined ones I have to have them for reference.
Another excellent tuner is the classic Boss Tu-3.
I’m using a Boss TU-3. I also like the Korg Pitchblack. Borh are $99 (cheaper for a used one).
Also, you can use either one like a brick. You know… just in case you need a brick. I’m just trying to say they’re solidly built.
I have the Korg pitchblack as well. Solid reasonably priced pedal tuner.
After years of tuning guitars and sax by ear, it’s a Peterson Strobostomp for me. I’ve owned lots and lots of tuners - from throwaway clip-ons to a massive laboratory-grade tuner (now the cost of that one was $$$).
You can always find cheaper than a Strobostomp, but I’ve never found better.
I have a Kong I’m not using Should gift it forward
This is 100% true! It’s called "unconscious incompetence 
Also, you often only find what you like by finding out what you don’t like.
I had a job designing fruit sorting equipment and the boss was always pretty vague when we were starting out on a project. I asked him if we could spend more time sorting out the details first so we wouldn’t have to do everything 3x and he said "I don’t always know what I want but i’ll know what i don’t want when i see it. 
Every damn client I’ve ever done work for has lived by this mantra. The bastards.
For my level of playing, the PolyTune Clip Tuner is just fine
And UniTune would probably have been enough, as the poly-thing is not really meant for bass.
And here’s if you want to dive deep into the subject of (clip-on) tuners 
If anyone is interested, I ended up purchasing through Musicians Friend, which is also Guitar Center, sort of. Based on a recommendation from one of the forum members, I reached out to Daniel Refsdal, who is a Gear Advisor with MF, but with a GC email address. I figured that all of their products come from the same warehouse, so it doesn’t really matter which road I take. I was upfront with him told him that I was price shopping and wanted to see what he could do. He was super nice, didn’t try to upsell me on anything like extra coverage, and made some suggestions on things like straps, cables, & a stand. The order took 45 mins & he never seemed to be in a rush. He said it would take 3-5 days to ship & the amp shipped the same day. He did get me a discount on my order as well. As my first experience goes, so far I’m happy with his service. Message me and I will send you his info if you are interested.
Congrats. Glad you had a great buying experience.
Hint: It won’t be your last. 
I use a clip tuner mostly. I’m not sure where my Peterson clip on is, one of my gig bags I’m sure, but I’ve used others. Peterson is the most accurate, but right up there is the Snark Air. I have done side by side testing with the Peterson and Air, and they performed equally.
What I like about both of these is they pick up low notes like B or Drop D, which other clip ons struggle with IME.
And the Air is rechargeable by a mini USB port
For $25, it’s my daily tuner
I have an Ordo clip on tuner but I’m not too impressed with it. For the E and A I have to pluck seriously hard for it to register with the tuner. Not so bad for the D and G. But a real pain all the same.
I also have a Zoom B3n multi-effects pedal and that also has a tuner which is much, much easier to use. So I only use the clip on if I’m doing a little practice without pedal.
Another alternative is an app for your phone. I have the free Fender tuner app which is fine but I originally got it for an acoustic and, of course, you have to have the bass plugged into an amp before that one can work.
That’s a great tuner, it’s what I used when I had one too.