IEMs have a learning curve - if you show up at a gig, and expect to go ampless/in ears without any rehearsal time using the concept, you're going to come away bitter, thinking the concept sucks. The concept doesn't suck, you just haven't put in the time and effort to figure it out. I worked for Shure for my entire career, and when we started working on in ears, the first thing we did as put together an ad hoc band, and try out the concept - the earbuds available at that time didn't work well at all for bass, and I, (the bassist in this band) was the first person to pull out my earbuds. The concept didn't suck, but the gear at that time did, and none of us had any experience using in ears. After we made some decent earbuds, I've been happily playing with in ears on gigs for over 30 years. I used to do a small coffee-house vibe gig (with a harp, if the helps your picture) where I used an amp, but that gig is no longer in my rotation, and now, all my gigs are ampless.
The beauty of the concept is, if you put in the time to learn how to use IEM's, you can get a much cleaner mix to your ears, and you can transport that mix anywhere. The band can be in their happy place wherever they go. It also greatly cleans up the FOH mix - what's coming off the stage is usually not very good sounding with wedges and amps, and the poor FOH person has to try to make a mix with that in the mix. With in ears, the stage is quiet enough that the sound person can make a mix from scratch - it's more like mixing an album than mixing live. Ultimately, it's better sound for everyone involved, but you gotta put in the time to learn how to use it.
I play places from a little 400 seater (probably 700 fire code) up to a 7500 seater. IEM's help the audience the most in the little places - it tames the sound coming off the stage. IEM's help the performers the most in the big places - some of the stages I play on, we spread people out enough that it would never work well with wedges - all the long delays make a big stage hard to play on at times, and the reflections off the back wall in a big indoor space can be jarring, but with in ears, you block that; you get to be in your protected bubble of familiarity.
I don't currently play anywhere there is an electronic kit, but I have in the past - the kits are still a ways from being friendly to the drummer, but they do solve a big problem in small spaces - a good drummer may not be happy, but a good drummer can usually deal with them. The smaller places I play, the drummer is in a box; the bigger places, there are shields - sometimes only minimal shields (the little circular plexiglass cymbal shields are enough is some places to make things work well).
I live in a townhouse, where I practice in headphones - I hear everything very clearly. My gigs are all on in ears - I literally only hear my bass through speakers on very rare occasions - workshops and things where I play through an amp. There is, when you get on a stage that moves well, and have a FOH person that loves low end, a really powerful feeling having clear, precise audio in your ears, and shaking in your feet from your lower notes. It's not the same experience as blasting your ears on a loud stage, but I wouldn't trade for that at this point.
P.S. All of the venues I play at (even the smallest ones) have PA's that are very capable of handling a bass guitar - there is no bass amp cabinet available that will do the fundamentals of a 5 string justice like a really good PA.
