Part of the issue is what you're optimizing for. If you have yearly net-metering, and you just want to max out the number of kWh you generate over the year, vertical probably isn't that great. If you are off-grid or are paid hourly based on power prices or some other scheme, you generally want to maximize your worst-case power production rather than maximize yearly production. Generally batteries are only sized for a few days worth of storage or so. You can't store power from the summer and use it in the winter. Vertical panels at high latitudes also produce more power earlier and later in the day when the sun is really low. Bifacial vertical panels also generally get more bifacial gain, especially on cloudy days.

It's really a question of maximizing worst-case performance vs. average-case performance.

And usually you have enough power during midday but not in the mornings and evenings, where these would produce the most power, sort of flattening the power curve.

Also panels are really cheap, like 70€ per piece

This is still conventional wisdom, yes. It assumes that you need to maximise utilisation of solar panels, and act as if they are rare and expensive. But they are now neither rare nor expensive any more.

Also, as the other comment pointed out, if you "maximize area that is facing the sun", you get most generation at mid-day. Adding in some generation that is most active in early and late day balances that out, as most power is used then.

And you can just throw more panels at the problem. It's not a constraint any more.

OP has 370W bi-facial panels that cost $100, I recently had solar installed the in UK with 465W single-face panels which would have cost ~£100 each to buy in small quantities, my installer clearly paid less (and charged 3x).

It has also been my experience that a few degrees off with decent enough sun (and we don't get amazing sun here in the UK) makes practically no difference to the generation; my arrays are facing E-SE and S-SW and I can slightly exceed the rated specs in the peak of summer when the sun is mid-way between both arrays and not pointing "directly" at either.

There are a lot more considerations to get into e.g. in areas with lots of snow verticals are significantly less affected and benefit more from reflection, in summer vertical E/W bifacials have a “double hump” which provides more generation in the morning and evening, verticals take less floor space so you might be able to get extra panels or get panels at all, N/S bifacials have better winter production unless your slanted panels are “detuned” from perfect summer angle (or even better have a tilt mount you can update every few months, but that is not cheap).

Because why not have a fence that at least generates some power instead of a fence that does nothing! Costs are not that much more, 2k is easily spent on a bigger fence and this way, you don't have to get up and hustle, our fence does it for you!

When vertical not much of an issue and the reflection from the snow appears to work well with bifacial.