I think this depends a very great deal on what your personal definition of a 'short burst' is. I know some people who will overwork themselves for weeks, then burn out and be unable to leave bed for weeks; this seems bad.
On the other hand, when I hyperfocus on something for several hours and then take the rest of the day off, I know I get significantly more and better work done than when I sort of idle away for sixteen hours, half-working and half-scrolling-Twitter.
I'm not sure why cycles on the scale of weeks seem much worse to me than cycles on the scale of hours, but one hypothesis I have is that it's about avoiding the lows going below a certain threshold. If I work very hard and am tired and hungry afterwards, that's fine; I'll rest and recover. If I ever reach a state where I'm too tired and hungry to be able to cook a good meal and go through some bedtime rituals, then I'll stop eating/sleeping properly. Once you hit a local minimum, you can be trapped there in a vicious cycle where you don't have the energy to take care of yourself properly, and you don't have any energy because you aren't taking care of yourself properly. Big highs & big lows are fine so long as you can recover from the big low and get another big high, but above a certain threshold you can't dig yourself out of certain holes without help.
If longer stretches of peak productivity produce worse burnout, then perhaps the key is keeping those stretches short enough that the burnout doesn't cross that threshold?
Also FWIW, in case others find this useful: there are various ideas about the optimum length of time to work before taking a break, e.g. the so-called 'Pomodoro technique' (a silly grandiose name for a small idea) which recommends 25 mins plus a short break.
In my experience 1 hour is just right. The kind of work I do is relatively intense intellectual stuff (e.g. programming, spreadsheets), and once I've got going I'm in a flow state which is inefficient to interrupt (as I'd just continue thinking about it during the break). So if I work until I notice I'm starting to flag, then check my watch, I almost always find I've been working for close to 1 hour. I find a break of roughly 15 minutes is about right - i.e. about long enough to make & drink a cup of tea. And it seems about the right kind of work:break time ratio.
This means that you can do about 3 hours intense work in a morning (3 hour-long chunks with breaks in between), and say 1-2 hours intense work plus additional semi-work (eg admin) in an afternoon. Assuming mornings are more suitable for intense work (as I suspect they are for most people). This totals 4-5 hours solid work - which as mentioned is my average.