I think that if you live near the departure airport and are going to the arrival airport's catchment area, then it can work. RYR's dispatch reliability is good due to them flying into (generally) smaller, less congested airports.
However, if anyone has had to book a flight under several weeks in advance, the fares quoted are very 'uncheap' indeed. It isn't realistic to travel without more than say 10-20kilos total(all-in) if one is holidaying/travelling/business tripping etc and if the airline is baulking at baggage, then it's not too clever. Most RYR passengers are, i'll wager, families travelling together, people visiting family, couples doing weekend/plus breaks, people doing sporting holidays/breaks and so on. ALL have baggage needs, it's normal..... Business clients will be in the minority, a niche market. However it is these 'hand-baggage warriors' who will benefit from RYR's policy and not the main group using the airline.
People are price sensitive and RYR obviously do offer very good fares if you can get them, but to gouge on generally accepted necessities is bad business IMHO. There is (was) too much 'fat' on the legacy carriers offerings, but being too thin is just as bad. With efficient handling I don't see why hold baggage needs to be a major hindrance, especially at smaller airports.
I've benefitted from crazy cheap fares (winter season 15.99 euro total return!) in the last few years and who would complain, but have also paid a decent amount and been left sleeping on an airport floor for 2 nights due to a late evening flight cancellation and left up the creek without a paddle (not RYR, but HLX) which definitely soured my relationship with that airline....
SHJ