Fair enough although I think self employed is viewed in a different way, and obviously your own income may have been the main reason for a positive decision, if you were in full employment.
My other half earns more after tax than what I earn before the taxman takes his share. The mortgage was very much granted on their earning capacity than mine, at least in the context of what a mortgage provider would be prepared to loan us and where we would otherwise be able to look for a place.
Also, if you have a permanent job, the amount of years that you have been in that full time employment is included in the mortgage application form and is given points in a process called "credit scoring" which contributes to the final decision. That is because you would be entitled to an increasing redundancy/severance pay award- not something the gig economy offers.
You would not necessarily be entitled to a redundancy payoff and even if you worked at a company long enough to qualify, there is no certainty that your payoff would be enough to pay off the rent / mortgage for more than a month.
In any case, if you are granted a mortgage or a tenancy, you are more likely to default if a gig economy employer suddenly withdraws anticipated working hours, leaving you short of the necessary income to make the payments. That could happen at any time, which would not help you sleep at night.
The risk of hours being withdraw would obviously need to be considered in the budget with the mortgage being granted on the assumption that for any given month the person does less hours than normal. So if you normally earn an average of £1000 a month then you would get the offer based upon only earning £800 a month. The responsibility would then fall on the worker to put a bit of money aside for the times that there are less hours.
As I say, a full time employed worker could be made unemployed at any time and would get zero income while looking for a job. The person who works in the gig economy would still be working some shifts and getting in some income even if not enough for any given month but then this refers back to the last sentence of the previous paragraph.
I just can't see any disadvantages, downsides, or responsibilities that are taken on by the employer. It is purely win-win for them with no need for any loyalty to the employee. You are probably viewed in line with office stationary.
If the employer is unreliable in terms of offering regular hours then good staff will look to get hours elsewhere. Bosses can't be complete dicks to their gig workers and some effort at loyalty is needed. It is better to try and be reliable and get people to want to come back and accept any hours than to get people who aren't familiar with your company.
From speaking to a lot of gig economy workers when I was able to go to concerts, it is better to bring back a person to help run the bar that has worked there before and know how the tills work and where the stocks are than someone who might have worked in a pub before but needs to ask colleagues where certain drinks are on the till screen or where spare bottles of drinks are in the cellar.
This is not to say that there isn't issues within the gig economy, but it isn't completely bad and there are plenty of people who make good money navigating the environment.