Remember: From our perspective, MS is a bunch of evil-empire joykills: lock-in, licensing, lucifier. But for most businesspeople, especially the non-startup bootstrappers, they are promethean, stealing fire from the mandarins of software engineering and bestowing it on worthy dreamers. FOSS is hard; cross-platform is hard; Siena is easy.
Personal context: I flinch instinctively when I see or hear MS' products. However, I'm responsible for ops at my job and I know damned well that there are several generations of small businesses for whom 'business management' is spelled 'A-C-C-E-S-S'. You can criticize this, you can complain about this, you can pay a bunch of bright young things to rewrite it Node or whatever, but you are never going to convince the businessowner that Access is a bad idea.
That same businessowner started one day in his garage with an empty Access database and remembers both it and those days with justified fondness. He's still just getting over not being able to 'improve' your schema on his laptop on lunch break so it 'makes more sense'.
I predict in ten years there will be a huge market for consultants getting businessses OFF this thing. But there will also be a huge pool of new businesses it helped create, so on balance, let me be the first to say: Hello World, Siena, and welcome.