Well, here's how I see it, and I'm glad I'm in the minority on this(owning a LOT of RE across the nation). I get at least 50 unsolicited scam/sales/robo calls and texts every month from RE 'buyers' wanting to engage me in commerce in direct violation of the strict TCPA. They are - relentless, and catching them, and fining them is a fools errand, although I've tried. There are good agents out there, and I've dealt with a few over the years, but the industry as a whole is a miasma of less than ethical operators. I know because I've been doing this for over 40 years. So, they can come out and have a look, and give me some hour of their precious time, as it will keep them off the phone, hassling some other property owner.
The first sentence of the OP: "We are thinking of selling our waterfront house and listing it ourselves". It doesn't say they refuse, or will never, just they are thinking of doing it themselves. Suppose one of these enterprising agents shows up, offers them a 2% commish, and makes the listing sale? Right there at the kitchen table, says 'go with me, I will sell it faster and for more money than your FSBO'. These sellers might change their mind. They don't KNOW they will FSBO, so unless there is a mind reader on the thread, I stand by my opinion.
I don't care either way if they FSBO or use an agent. The agency relationship works on a commission basis, and not an hourly rate. And, further, I've been doing this a while, and I would trust an active RE agent seller's CMA way, way more than an appraiser. I've seen appraisals vary by 25% on the same home within the same week. So if one wants to hire an appraiser, better hire three of them, because they are all going to be different by thousands of $$$
YMMV, objects in mirror, closed course pro driver, contents have settled, and may cause anal leakage.