If it’s a good solid roof, not leaking bad, Not blistered, and nice and tight when you walk on It, silicone can be good solution to extend the life. Looks like you have 2+ built ups over the original tin.
I would have your local supplier get you in touch with the gaco rep, give them a call/email some pictures. Silicone reps at least in my area seem to be very avalible and willing to help.
Because it is exposed asphalt they are most likely going to want you to prime it first, then hit any cracks, flashing junctures, and where you cut that hole with trowel grade mastic and fabric first, followed by rolling on two coats of silicone.
Done right it is a great product just have to follow the right steps for your particular roof, if not you are just wasting money, and it’s not cheap. A little research and a few calls helps, not something you just pick up at depot and throw on in an hour and magically fixes everything.